Feasibility of satellite quantum key distribution

TL;DR

This paper analyzes the feasibility of satellite-based quantum key distribution by modeling atmospheric effects, background noise, and error rates to estimate secure key generation rates for various configurations and protocols.

Contribution

It introduces a comprehensive model for atmospheric turbulence, noise, and error rates, evaluating secure key rates for satellite QKD with different protocols and configurations.

Findings

Secure key rates vary with atmospheric conditions and protocol choices.

Uplink and downlink configurations have different performance profiles.

Background noise significantly impacts the achievable key rate.

Abstract

In this paper we present a novel analysis of the feasibility of quantum key distribution between a LEO satellite and a ground station. First of all, we study signal propagation through a turbulent atmosphere for uplinks and downlinks, discussing the contribution of beam spreading and beam wandering. Then we introduce a model for the background noise of the channel during night-time and day-time, calculating the signal-to-noise ratio for different configurations. We also discuss the expected error-rate due to imperfect polarization-compensation in the channel. Finally, we calculate the expected key generation rate of a secure key for different configurations (uplink, downlink) and for different protocols (BB84 with and without decoy states, entanglement-based Ekert91 protocol).