Empirical Analysis of Spectrum Sharing Models Between Satellite and Terrestrial Networks in the Ka-Band in Nigeria

The Ka-band spectrum below 30 GHz hosts growing satellite broadband services including planned low-Earth orbit constellations while simultaneously being planned for terrestrial 5G backhaul applications, creating interference potential that demands empirically grounded spectrum sharing analysis specifically for Nigerian deployment conditions. This study empirically analyzes spectrum sharing models between satellite and terrestrial networks in the Ka-band within Nigeria's regulatory context, providing interference characterization and protection distance estimates relevant to NCC spectrum planning. A measurement-based empirical methodology was employed, with Ka-band downlink signal level measurements from operational geostationary satellite services collected at ten locations across the FCT and Enugu State under various atmospheric conditions. Interference budget analyses using ITU-R S.1525 and the aggregate interference model were conducted for terrestrial 5G backhaul links sharing the same Ka-band spectrum. Monte Carlo simulations incorporating measured channel variability parameterized the probability distribution of interference exceedance at satellite earth station receivers. Results indicate that a minimum geographic exclusion zone of 45 kilometers around major satellite earth stations in the FCT is required to maintain interference levels within the ITU-recommended I/N threshold of negative 12.2 dB for 99% of time under typical Nigerian atmospheric conditions. Dynamic spectrum access mechanisms that exploit satellite link utilization gaps could reduce exclusion zone requirements by 28%. The study provides empirically calibrated spectrum sharing parameters directly applicable to NCC's pending Ka-band frequency assignment planning processes. Keywords: spectrum sharing, Ka-band, satellite, 5G backhaul, interference analysis.