Visibility considerations in frequency sharing with low Earth orbit satellites

Recent proposals in data-relay satellite systems indicate the use of multiple low earth orbit (LEO) satellites. These systems usually consist of many small satellites, each of which stays above the horizon for around 15 minutes in each 100-minute orbit. Allocation of frequency bands to this service sharing with existing services, with communication links between fixed points, will require additional considerations. In addition to interference assessment between the shared systems, parameters relating to probability of time exposure should be considered in the evaluation for sharing feasibility. The model used to estimate these parameters in sharing analyses is described.