A method performed by a device for load balancing in a wireless communication system, the method comprising, obtaining (410, 420) measurement information of a plurality of terminals served by a first cell or a second cell, including first measurement information of a first terminal served by the first cell, second measurement information of a second terminal served by the first cell; and transmitting a control signal for switching a serving cell of the first terminal from the first cell to the second cell and for controlling power of the second terminal based on the first measurement information and the second measurement information, wherein the first measurement information includes information indicating a first optimal beam of the first cell and a first receiving strength of a reference signal transmitted through the first optimal beam of the first cell and information indicating a first optimal beam of the second cell and a first receiving strength of a reference signal transmitted through the first optimal beam of the second cell, wherein the second measurement information includes information indicating a second optimal beam of the first cell and a second receiving strength of a reference signal transmitted through the second optimal beam of the first cell and information indicating a second optimal beam of the second cell and a second receiving strength of a reference signal transmitted through the second optimal beam of the second cell, wherein an optimal beam is a beam having a highest reference signal received power, RSRP, among beams received by a terminal from a cell, wherein the first optimal beam of the first cell is a serving beam for the first terminal and the second optimal beam of the first cell is a serving beam for the second terminal, and wherein the controlling power of the second terminal comprises reducing or increasing the power of the second optimal beam of the first cell for the second terminal if the first optimal beam of the first cell for the first terminal is same as the second optimal beam of the first cell for the second terminal. obtaining (410, 420) measurement information of a plurality of terminals served by a first cell or a second cell, including first measurement information of a first terminal served by the first cell, second measurement information of a second terminal served by the first cell; and transmitting a control signal for switching a serving cell of the first terminal from the first cell to the second cell and for controlling power of the second terminal based on the first measurement information and the second measurement information, wherein the first measurement information includes information indicating a first optimal beam of the first cell and a first receiving strength of a reference signal transmitted through the first optimal beam of the first cell and information indicating a first optimal beam of the second cell and a first receiving strength of a reference signal transmitted through the first optimal beam of the second cell, wherein the second measurement information includes information indicating a second optimal beam of the first cell and a second receiving strength of a reference signal transmitted through the second optimal beam of the first cell and information indicating a second optimal beam of the second cell and a second receiving strength of a reference signal transmitted through the second optimal beam of the second cell, wherein an optimal beam is a beam having a highest reference signal received power, RSRP, among beams received by a terminal from a cell, wherein the first optimal beam of the first cell is a serving beam for the first terminal and the second optimal beam of the first cell is a serving beam for the second terminal, and wherein the controlling power of the second terminal comprises reducing or increasing the power of the second optimal beam of the first cell for the second terminal if the first optimal beam of the first cell for the first terminal is same as the second optimal beam of the first cell for the second terminal.