In a method of controlling transmit power for a user call migrating between a first entity and a second entity in a base station of a wireless communication system, power control may be performed, as a call of the user is migrated from the first to the second entity, or vice versa, based on an adjustment ratio value. Parameters for balancing transmit power as the user call is migrated from the first entity to the second entity may be selected so that any difference in transmit power does not adversely affect system performance.