Cooperative Dual Aerial IRS-Aided Satellite System: A Performance Analysis

This paper addresses the problem of masking effect in satellite communication by incorporating the benefits of aerial intelligent reflecting surface (AIRS). In this paper a cooperative dual-AIRS aided satellite system has been considered where a geostationary (GEO) satellite transmits signal to a masked ground node through two cooperative AIRS nodes. The AIRSs are considered to move in a circular trajectory. Realistic physical environment and heterogeneity of space, air and ground are taken into consideration to model channel fading and large scale path loss of space-to-air, air-to-air and air-to-ground links of the proposed model. The space-to-air link is modeled using Shadowed Rician distribution, while LoS channel is considered between two AIRS nodes and Nakagami-$m$fading between aerial and ground node. With these channel models, we derive the closed-form expressions for probability density function, cumulative distribution function and moment generating function of the end-to-end signal-to-noise ratio (SNR) in the form of generalized-$K$($K_{G}$) distribution. Using these expressions, we further derive the closed-form expressions for exact and asymptotic error probability, outage probability and ergodic capacity. The accuracy of$K_{G}$distribution is validated through Kullback-Leibler (KL) divergence measure. Furthermore, simulation results are provided to validate the accuracy of derived expressions and investigate the effect of satellite elevation, number of reflecting elements, impact of imperfect CSI and mobility of AIRSs on the performance of the system. The performance is also compared with decode-and-forward (DF) UAV relay aided and single AIRS aided satellite systems and the comparison shows that despite of increased multiplicative pathloss the proposed dual AIRS aided system outperforms both the aforementioned schemes.