Optimum Power Allocation Based on Channel Conditions in Optical Satellite Downlinks

Abstract

The integration of optical satellite links in the next-generation networks and in the fifth generation cellular systems has been proposed in order to guarantee the handling of the extreme data traffic growth and the high-pitched demand for networks’ resources. The optical satellite communication downlink is studied and more specifically, a geostationary satellite with multiple transmitters and an optical ground station with multiple receiving terminals are considered. In this contribution a novel power allocation methodology is proposed for the downlink. The allocation methodology takes into account the scintillation effects due to atmospheric turbulence and maximizes the ergodic network capacity under total expected power and peak power constraints. The analytical optimizing schemes are based on convex optimization methods and have been inspired by waterfilling algorithm. We present emulated power allocation results using real experimental downlink data from ARTEMIS optical satellite campaign and then we investigate the performance of the proposed algorithm with extended numerical results and comparison with other allocation policies. In particular, the new power allocation strategy achieves the highest spectral efficiency, according to the power constraints, for various channel conditions and attenuation profiles and also surpasses two simple baseband allocation methods by intelligently taking advantage of the number of channels and the total expected power.