The directional transmission can be applied to wide range of wireless system, which ranges from indoor WPAN to outdoor cellular system. In the system which uses directional transmission, the interference estimation will be different from that with omni-directional transmission, because the interference from other cell will come from various directions. To solve this problem, we have proposed adaptive interference estimation scheme which uses directional transmission. Through the system level multi-cell simulation which is based on the actual wireless environment, we have shown that our proposed scheme can improve the performance of system in the view of spectral efficiency and fairness.