Transmission method, radio base station and mobile station

A radio base station of a second cell in a radio communication system where a first cell and the second cell are provided, the first cell is allocated to a first transmission band, the second cell is allocated to a second transmission band that is different from the first transmission band and overlaps with the first transmission band, and a first synchronization channel is transmitted in a first partial band of the first transmission band, the radio base station comprising:

• a transmitter configured to transmit a second synchronization channel in a second partial band of the second transmission band, the second partial band being a central band of the second transmission band and different from the first partial band,
• wherein an area of the second cell is smaller than an area of the first cell,
• wherein the first partial band used for transmitting the first synchronization channel is a central band of the first transmission band, and the second transmission band of the second cell includes the first partial band, and
• wherein the first partial band and the second partial band partly overlap each other while a center frequency of the first partial band and a center frequency of the second band are different.

A mobile station in a radio communication system where a first cell and a second cell are provided, the first cell is allocated to a first transmission band, the second cell is allocated to a second transmission band that is different from the first transmission band and overlaps with the first transmission band, and a first synchronization channel is transmitted in a first partial band of the first transmission band, the mobile station comprising:

• a controller configured to control bands used for detecting synchronization channels in a cell search, within the first partial band or, within the first partial band and a second partial band which is a central band of the second transmission band and used for transmitting a second synchronization channel in the second cell to which the mobile station is admitted to access,
• wherein an area of the second cell is smaller than an area of the first cell,
• wherein the first partial band used for transmitting the first synchronization channel is a central band of the first transmission band, and the second transmission band of the second cell includes the first partial band, and
• wherein the first partial band and the second partial band partly overlap each other while a center frequency of the first partial band and a center frequency of the second band are different.

A radio communication system comprising a first radio base station of a first cell, a second radio base station of a second cell, and a mobile station, wherein

• the first cell is allocated to a first transmission band, and the second cell is allocated to a second transmission band that is different from the first transmission band and overlaps with the first transmission band,
• the first radio base station comprises a transmitter configured to transmit a first synchronization channel in a first partial band of the first transmission band, the first partial band being a central band of the first transmission band,
• the second radio base station comprises a transmitter configured to transmit a second synchronization channel in a second partial band of the second transmission band, the second partial band being a central band of the second transmission band and different from the first partial band,
• an area of the second cell is smaller than an area of the first cell,
• the second transmission band of the second cell includes the first partial band used for transmitting the first synchronization channel, and
• the first partial band and the second partial band partly overlap each other while a center frequency of the first partial band and a center frequency of the second band are different.