Base Station, Terminal And Method Thereof

A base station, terminal and method are provided. A method performed by a terminal includes the following steps: receiving a media access control (MAC) control element (CE) for activating a secondary cell (SCell) from a base station; receiving a physical a downlink control channel (PDCCH) command for initiating a random access procedure on the SCell from the base station; initiating a random access procedure based on the PDCCH order; and receiving a MAC CE including a timing advance command (TAC) based on a random access procedure from the base station. 提供种基站、终端及其方法。由终端执行的方法包括：从基站接收用于激活辅小区(SCell)的媒体访问控制(MAC)控制元件(CE)；从所述基站接收用于在所述SCell上发起随机接入过程的物理下行链路控制信道(PDCCH)命令；基于所述PDCCH命令发起随机接入过程；和基于来自所述基站的随机接入过程接收包括时序提前命令(TAC)的MAC CE。