Optimization design of LEO communication constellation considering link interference

The issue of the interference from the Low Earth Orbit (LEO) communication constellation to the Geostationary Earth Orbit (GEO) satellite links has become increasingly severe. Considering the impact of link interference during the design phase of LEO constellation can help mitigate this issue, this paper proposes an optimized design method for LEO communication constellation that incorporates link interference consideration. An improved interference exclusion zone is introduced and a semi-analytical interference assessment model is established to enhance computational efficiency. First, a multi-objective optimization model for LEO constellation design is established, with the constellation orbital and configuration parameters as design variables, and the LEO constellation construction cost and interference levels on GEO satellite links as objectives. Constraints include the communication coverage, ground station tracking strategy, uninterrupted communication of constellation, and configuration limitations. Second, an improved interference exclusion zone is designed, and the interference level of the constellation is evaluated using the time proportion of LEO satellites passing through this zone. Finally, the non-dominated sorting genetic algorithm is employed to solve the optimization problem. Results demonstrate that the improved interference exclusion zone can more effectively characterize harmful interference zones under different orbital altitudes and ground station distributions. The proposed time proportion metric exhibits a similarity of 0.998 with the traditional interference evaluation index while achieving a 40-fold acceleration in the computational efficiency. The optimization of the satellite phase reduces the interference level on GEO downlinks by over 5% without the additional cost, and the optimization of the constellation configuration reduces the interference level by more than 90% with a cost increase of less than one-third of the original design.