In this paper, we propose an efficient and robust interference mitigation technique based on a nullsteering multiuser multiple-input multiple-output (MU-MIMO) spatial division multiple access (SDMA) scheme for frequency sharing between IMT-Advanced and fixed satellite service (FSS). In the proposed technique, the conventional precoding matrix for SDMA unitary preceded (UPC) MIMO proposed by the authors is modified to construct nulls in the spatial spectrum corresponding to the direction angles of the victim FSS earth station (ES). The frequency sharing results are given in terms of interference power and minimum separation distance in the co-channel. Simulation results shows that our mitigation technique reduces interfering power by about 60 dB and can meet the maximum permissible interference power condition in almost separation distances. Therefore it can be concluded that the proposed mitigation technique in this paper is highly efficient in terms of reducing the separation distance as well as robust against DOE estimation errors.

In this paper, we propose a methodology for calculating the necessary spectrum requirements of aeronautical mobile airport communication system (AeroMACS) to provide various airport communication services. To accurately calculate the spectrum requirement, it is necessary to evaluate the AeroMACS traffic demand of the peak time and statistical data on the packet traffic generated at the airport. Because there is no AeroMACS traffic model and real trace data, we have developed the AeroMACS traffic simulator based on the report of Single European Sky Air Traffic Management Research (SESAR). To calculate the spectrum requirements, the AeroMACS traffic simulator is combined with the methodology of ITU-R M.1768-1. The developed traffic simulator reflects AeroMACS traffic priorities and can generate the required traffic according to its location in the airport. We observed the spectrum requirement by changing the number of sectors and the spectral efficiency. To show the feasibility of our methodology, we applied it to the case of Incheon International Airport in Korea. The simulation results show that the average bandwidth of 0.94 MHz is required in the ground area and 8.59 MHz is required in the entire airport.