ITU has considered the 3,400$sim$4,200 MHz band, which is allocated worldwide on a primary basis to the FSS, as a candidate band for future development of IMT system. In this band, this paper presents the results of the sharing studies performed between FSS and IMT systems through the theoretical and simulation analysis on the interference from multiple IMT base stations into a receiving FSS earth station considering the interference mitigation techniques such as antenna tilt angle and 3 sectors on the IMT base station. By using the long-term and short-term interference threshold, the coordination areas for the FSS earth station are provided to share frequency in 3,400$sim$4,200 MHz band between FSS earth station and multiple IMT base stations in future.