An operation method of a CP may include: collecting, from terminals or ANs, information on AN(s) to which each of the terminals is connectable, and determining a set of active AN(s) based on the information; adjusting connections between active AN(s) and the terminals based on cooperative transmission constraints; calculating first energy efficiency according to the active AN(s), and calculating second energy efficiency in a state in which at least one AN of active AN(s) is deactivated or activated; and maintaining the set of active AN(s) when second energy efficiency is not improved over first energy efficiency, and updating the set of active AN(s) by excluding or further including the at least one AN when second energy efficiency is improved over first energy efficiency, and performing iteratively from the calculating first energy efficiency and second energy efficiency.