Cislunar Communication Performance and System Analysis with Uncharted Phenomena

TL;DR

This work addresses the challenge of robust cislunar communication for future CSNs by introducing a unified link-model that combines brightness-temperature–driven receiver noise with additive symmetric alpha-stable (AS$\alpha$SN) non-Gaussian noise and Nakagami-$m$ fading. The authors derive closed-form lower bounds on ergodic capacity and upper bounds on outage probability for the AS$\alpha$SN channel, along with the pdf of the instantaneous SNR, and develop a Blahut-Arimoto–based numerical approach adapted to fading channels to approximate ergodic capacity. They apply the framework to the Lunar Gateway link, relating environmental variations to performance across S and Ka bands and providing system-level insights for mission design, including TB impacts, fading scenarios, distances, and transmit power. The findings highlight the significant influence of brightness temperature and non-Gaussian noise on achievable data rates and reliability, offering quantitative guidance for CSN design and operation in dynamic cislunar environments.

Abstract

The Moon and its surrounding cislunar space have numerous unknowns, uncertainties, or partially charted phenomena that need to be investigated to determine the extent to which they affect cislunar communication. These include temperature fluctuations, spacecraft distance and velocity dynamics, surface roughness, and the diversity of propagation mechanisms. To develop robust and dynamically operative Cislunar space networks (CSNs), we need to analyze the communication system by incorporating inclusive models that account for the wide range of possible propagation environments and noise characteristics. In this paper, we consider that the communication signal can be subjected to both Gaussian and non-Gaussian noise, but also to different fading conditions. First, we analyze the communication link by showing the relationship between the brightness temperatures of the Moon and the equivalent noise temperature at the receiver of the Lunar Gateway. We propose to analyze the ergodic capacity and the outage probability, as they are essential metrics for the development of reliable communication. In particular, we model the noise with the additive symmetric alpha-stable distribution, which allows a generic analysis for Gaussian and non-Gaussian signal characteristics. Then, we present the closed-form bounds for the ergodic capacity and the outage probability. Finally, the results show the theoretically and operationally achievable performance bounds for the cislunar communication. To give insight into further designs, we also provide our results with comprehensive system settings that include mission objectives as well as orbital and system dynamics.

Figures (8)

• Figure 1: The uplink communication from the lunar surface user to the Lunar Gateway. The exaggerated view of cislunar space in which the Lunar Gateway orbits in near-rectilinear halo orbit (NRHO) while the Moon and Earth move in their orbits. One of the lunar surface users represents the communication terminal of the lunar mission and transmits information.
• Figure 2: Comparisons of the closed-form lower bound for ergodic capacity in equation (\ref{['ergodic_bound']}) and numeric capacity approximation algorithm with $m=1$ and $\alpha \in \left \{1.8, 1.9, 2\right \}$.
• Figure 3: Comparisons of the closed-form lower bound for ergodic capacity in equation (\ref{['ergodic_bound']}) and numeric capacity approximation algorithm with $m=5$ and $\alpha \in \left \{1.8, 1.9, 2\right \}$.
• Figure 4: Comparisons of the closed-form lower bound for ergodic capacity in equation (\ref{['ergodic_bound']}) and numeric capacity approximation algorithm with $m=15$ and $\alpha \in \left \{1.8, 1.9, 2\right \}$.
• Figure 5: The comparison of the ergodic capacity for the Ka bandwidth the lower bound in equation (\ref{['ergodic_bound']}) depending on the brightness temperature and under different system settings.

Theorems & Definitions (7)

• proof
• Lemma 1
• proof
• Theorem 2
• proof
• Theorem 3
• proof