A device and method in a wireless communication system, the device including an access determination unit configured to determine an access requirement of a user equipment (UE); and a control unit configured to switch a target small cell of the device from a closed state to an open state based on the access requirement of the UE, and reallocate to the target small cell a new physical cell identifier different from the physical cell identifier used in the closed state. A physical cell identifier can be dynamically allocated in accordance with the open/closed state of the small cell, reducing the burden of cell planning and maintenance cost, and having greater flexibility.