Coverage Performance Analysis of Satellite-Terrestrial Integrated Radio Access Networks

To enhance coverage and improve service continuity, satellite-terrestrial integrated radio access networks (STIRANs) have been seen as an essential trend in the development of 6G. However, there is still lack of theoretical analysis on its coverage performance when low-earth-orbit (LEO) satellites are considered. To fill this gap, we establish a system model to characterize a typical scenario where LEO satellites and terrestrial base stations (BSs) are both deployed, which features the orbit model of satellites, a deployment hole of BSs centered at a typical user and practical satellite antenna radiation pattern. With stochastic geometry (SG), the downlink coverage probability is analyzed under the setting where LEO satellites and BSs occupy distinct frequency band. Based on the distribution of the nearest serving distance, the expression of coverage probability is derived. Via extensive simulation, the correctness of theoretical derivations is verified and the influence of network design parameters is demonstrated, including satellite's density and orbit polar angle. Moreover, the performance improvement brought by STIRANs over LEO satellite network and terrestrial network is highlighted.