Diversity Scheme based FSO/RF Hybrid Systems in SAGIN with Interference and Outdated CSI

Satellite-aerial-ground integrated networks (SAGIN) is an effective means to achieve global seamless coverage and real-time connectivity. In this paper, we investigate the performance of hybrid free-space optical (FSO) and radio frequency (RF) relay systems in SAGIN where the effect of co-channel interference (CCI) and outdated channel station information (CSI) are taken into account. Specifically, we propose different relay strategies considering diversity scheme which are achieved by deploying an additional ground station (GS) and a high-altitude platform (HAP). The FSO link and RF link are modeled by Gamma-Gamma distribution and Nakagami-m distribution, respectively. Then, we derive the cumulative distribution function (CDF) expression of RF link considering CCI and outdated CSI, and the expression of outage probability for our proposed hybrid FSO/RF systems is also given. Comparison scheme is adopted to show the strength of our proposed scheme. Numerical results show that the interference numbers and intensity of can seriously deteriorate system performance, and multiple antennas can further improve system performance.