Wireless communication terminal device and method for controlling transmission power

A radio communication terminal apparatus, comprising:

• a control circuit, which, in operation, controls a transmission timing and a transmission power of a first subframe on a first component carrier (CC) out of multiple CCs,
• wherein the first subframe on the first CC overlaps with a second subframe on a second CC along a time axis to form an overlapping portion,
• said controlling of the transmission timing and the transmission power of the first subframe on the first CC includes adjusting the transmission power of the first subframe on the first CC in units of symbols within the first subframe so that a sum of the transmission powers of the first subframe on the first CC and the second subframe on the second CC at the overlapping portion does not exceed a permitted value,
• in a case where the overlapping portion is an initial symbol in the first subframe overlapping a last symbol in the second subframe, said controlling of the transmission timing and the transmission power of the first subframe on the first CC includes
• lowering the transmission power of the initial symbol in the first subframe for a predetermined time interval starting from a beginning of the initial symbol in the first subframe,
• starting, subsequent to the predetermined time interval, a transmission power transient period, and
• increasing, subsequent to the transmission power transient period, the transmission power of the initial symbol in the first subframe such that a sum of the transmission powers of the initial symbol in the first subframe and the last symbol in the second subframe at the overlapping portion does not exceed the permitted value, and
• the predetermined time interval is set according to a time difference between a transmission time of the first CC and a transmission time of the second CC;
• and
• a transmission circuit coupled to the control circuit which, in operation, transmits a signal at the controlled transmission timing with the controlled transmission power in the first subframe on the first CC.