Cognitive Region Design for Overlay Cognitive Satellite Terrestrial Networks

Abstract

In this letter, we investigate an overlay cognitive satellite terrestrial network (OCSTN), where the secondary terrestrial network assists the primary satellite communication in exchange for the opportunities of spectrum access. To achieve a win-win cooperation of the satellite and terrestrial networks in the OCSTN, we propose a cognitive region to determine the conditions that terrestrial nodes can work as effective relays to cooperate with the satellite network in a time-splitting spectrum sharing manner. Specifically, we first analyze the ergodic rates of the satellite and terrestrial networks. On this basis, we design a cognitive region seeking the feasible location set of the secondary relay and the corresponding range of time splitting ratios, which can improve the satellite communication performance while enabling the transmission of terrestrial network.