Modeling and Performance Analysis of IoT-over-LEO Satellite Systems under Realistic Operational Constraints: A Stochastic Geometry Approach

TL;DR

This work addresses IoT-over-LEO satellite performance under realistic constraints by modeling IoT devices with a finite-area binomial point process in a spherical cap of radius $R_c$ and satellites with a binomial process on a sphere of radius $r_e+H$. It develops a two-link end-to-end framework, using Nakagami fading for the terrestrial-to-satellite uplink and Shadowed-Rician fading for the feeder link, while explicitly accounting for uplink and downlink interference and limited satellite coverage. The authors derive distance distributions, derive analytical expressions for coverage probability and average ergodic rate on both links, and validate them via Monte Carlo simulations, revealing how finite-area size, beamwidth, and satellite density influence network reliability. The results provide actionable insights for constellation deployment and device distribution planning, emphasizing the trade-offs between service-link reliability and feeder-link interference under realistic operational constraints.

Abstract

Current theoretical studies on IoT-over-LEO satellite systems often rely on unrealistic assumptions, such as infinite terrestrial areas and omnidirectional satellite coverage, leaving significant gaps in theoretical analysis for more realistic operational constraints. These constraints involve finite terrestrial area, limited satellite coverage, Earth curvature effect, integral uplink and downlink analysis, and link-dependent interference. To address these gaps, this paper proposes a novel stochastic geometry based model to rigorously analyze the performance of IoT-over-LEO satellite systems. By adopting a binomial point process (BPP) instead of the conventional Poisson point process (PPP), our model accurately characterizes the geographical distribution of a fixed number of IoT devices in a finite terrestrial region. This modeling framework enables the derivation of distance distribution functions for both the links from the terrestrial IoT devices to the satellites (T-S) and from the satellites to the Earth station (S-ES), while also accounting for limited satellite coverage and Earth curvature effects. To realistically represent channel conditions, the Nakagami fading model is employed for the T-S links to characterize diverse small-scale fading environments, while the shadowed-Rician fading model is used for the S-ES links to capture the combined effects of shadowing and dominant line-of-sight paths. Furthermore, the analysis incorporates uplink and downlink interference, ensuring a comprehensive evaluation of system performance. The accuracy and effectiveness of our theoretical framework are validated through extensive Monte Carlo simulations. These results provide insights into key performance metrics, such as coverage probability and average ergodic rate, for both individual links and the overall system.

Figures (11)

• Figure 1: Illustration of the IoT-over-LEO satellite system.
• Figure 2: Illustration of the system's geometric relationships, where the yellow, blue and green spherical caps denote the finite-size ground area $\mathcal{A}_{\textrm{T}}$, satellite coverage $\mathcal{A}_{\textrm{C}}$ and distribution region of visible satellites $\mathcal{A}_{\textrm{S}}$, respectively.
• Figure 3: CP as function of threshold $T_1$, given different finite-size area radii $R_{\rm{c}}$.
• Figure 4: CP as function of threshold $T_1$, given different satellite antenna beamwidth $\varphi_{\textrm{s}}$.
• Figure 5: CP as function of threshold $T_1$, given different numbers of satellites $N_{\textrm{S}}$.

Theorems & Definitions (28)

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