Terminal device, method, and integrated circuit

A MAC entity of a terminal device of the present invention determines whether or not a TAT associated with a TAG of a PSCell including an SCG expires, and on the basis of determining that the TAT associated with the TAG including the PSCell expires, notifies an RRC entity of the terminal device of a notification indicating that a random access procedure is required when the SCG is activated. 本发明的终端装置的MAC实体判断与包括SCG的PSCell的TAG建立了关联的TAT是否期满，基于判断为与包括所述PSCell的TAG建立了关联的TAT期满，对终端装置的RRC实体通知表示在激活所述SCG时需要随机接入过程的通知。