Radio terminal, radio base station, channel signal forming method and channel signal receiving method

An integrated circuit to control a process, comprising:

• generating circuitry, which, in operation, generates control information, which is mapped on a user equipment (UE) specific search space in a first component carrier and which has a first basic information size of control information,
• wherein the first basic information size is determined by a first determining method, which is different from a second determination method for determining a second basic information size of control information mapped on a common search space in the first component carrier;
• and
• transmitting circuitry, which, in operation, transmits the generated control information to a user equipment (UE),
• wherein when uplink allocation information is absent in the first component carrier, the first basic information size is determined according to an information size determined from a downlink bandwidth of the first component carrier.

An integrated circuit comprising circuitry, which, in operation:

• generates control information, which is mapped on a user equipment (UE) specific search space in a first component carrier and which has a first basic information size of control information,
• wherein the first basic information size is determined by a first determining method, which is different from a second determination method for determining a second basic information size of control information mapped on a common search space in the first component carrier and which is different from a third determination method for determining a third basic information size of control information mapped on a search space in a second component carrier that is different from the first component carrier;
• and
• controls transmitting the generated control information to a user equipment (UE).

An integrated circuit comprising circuitry, which, in operation:

• generates control information, which is mapped on a user equipment (UE) specific search space in a first component carrier and which has a first basic information size of control information,
• wherein the first basic information size is determined by a first determining method, which is different from a second determination method for determining a second basic information size of control information mapped on a common search space in the first component carrier;
• and
• controls transmitting the generated control information to a user equipment (UE),
• wherein when uplink allocation information is absent in the first component carrier, the first basic information size is determined according to an information size determined from a downlink bandwidth of the first component carrier.