Performance of Multibeam Very High Throughput Satellite Systems Based on FSO Feeder Links with HPA Nonlinearity

TL;DR

This paper evaluates the performance of multibeam VHTS systems using FSO feeder links with HPA nonlinearity, considering beam wander, pointing errors, and interference mitigation, providing exact and asymptotic performance metrics.

Contribution

It introduces a comprehensive performance analysis of multibeam VHTS systems with FSO links accounting for HPA nonlinearity and interference, deriving closed-form expressions for key metrics.

Findings

Closed-form expressions for outage probability, BER, and capacity.

Asymptotic high-SNR performance results.

Impact of beam wander and pointing errors on system performance.

Abstract

Due to recent advances in laser satellite communications technology, free-space optical (FSO) links are presented as an ideal alternative to the conventional radio frequency (RF) feeder links of the geostationary satellite for next generation very high throughput satellite (VHTS) systems. In this paper, we investigate the performance of multibeam VHTS systems that account for nonlinear high power amplifiers at the transparent fixed gain satellite transponder. Specifically, we consider the forward link of such systems, where the RF user link is assumed to follow the shadowed Rician model and the FSO feeder link is modeled by the Gamma-Gamma distribution in the presence of beam wander and pointing errors where it operates under either the intensity modulation with direct detection or the heterodyne detection. Moreover, zero-forcing precoder is employed to mitigate the effect of inter-beam interference caused by the aggressive frequency reuse in the user link. The performance of the system under study is evaluated in terms of the outage probability, the average bit-error rate (BER), and the ergodic capacity that are derived in exact closed-forms in terms of the bivariate Meijer's G function. Simple asymptotic results for the outage probability and the average BER are also obtained at high signal-to-noise ratio.