Apparatus and method for reducing interference and saving energy in femto/pico cell of hierarchical cell structure

An apparatus of a small base station for performing power management, the apparatus comprising:

• a power manager configured to determine whether a notify message indicating that a subscribed terminal enters a macro base station that includes an off-small base station is received from the macro base station under a closed access mode, when the notify message is received, determine whether a service is providable to the subscribed terminal, and when the service is providable to the subscribed terminal, turn on the off-small base station;
• and
• a transceiver configured to communicate with the subscribed terminal and the macro base station.

A small base station that performs power management, the small base station comprising:

• a transceiver configured to communicate with terminals and a macro base station;
• and
• a power manager configured to determine whether a subscribed terminal has entered a cell of the macro base station that includes the small base station that is currently in an off-state during a closed access mode, determine whether a service is providable to the subscribed terminal when the subscribed terminal has entered the cell of the macro base station when the small base station is currently in the off-state during the closed access mode, and turn on the small base station when the service is providable to the subscribed terminal.