Mobility issues in cognitive satellite communication systems operating in Q/V-band

In this paper, we analyze the performance of spectrum sensing in a cognitive satellite communication system adopting a stochastic optimization. The focus is on the user link of a geostationary satellite system and on a multi-hop terrestrial network with moving secondary users operating in Ka-band or in Q/V-band. We propose a stochastic joint optimization method that allows the minimization of the energy consumption of the spectrum sensing of the multi-hop secondary network for scenarios with time-varying energy due to the mobility of the secondary users, under constraints on the detection performance of the sensing and the number of network hops. The optimal closed-form solution of the optimization problem is derived assuming the constant velocity model for the secondary users. The proposed technique has been proven with different types of propagation impairments, by considering satellite communications acting as primary user in the presence of interference with very low signal-to-noise ratio. Finally, the results show that the proposed framework is accurate and robust to high mobility scenarios of the secondary network while preserving the reliability of detecting the existence of the primary users.