Coverage Analysis of Dynamic Coordinated Beamforming for LEO Satellite Downlink Networks

TL;DR

This paper analyzes how dynamic coordinated beamforming enhances coverage in LEO satellite downlink networks, providing analytical models and showing significant coverage improvements with increased antennas and optimal cluster sizes.

Contribution

It introduces analytical expressions for coverage probability in satellite networks with coordinated beamforming, considering spatial distributions and cluster sizes, validated by simulations.

Findings

Coverage significantly improves with more antennas per satellite.

Optimal cluster size increases with satellite density.

Analytical models closely match simulation results.

Abstract

In this paper, we investigate the coverage performance of downlink satellite networks employing dynamic coordinated beamforming. Our approach involves modeling the spatial arrangement of satellites and users using Poisson point processes situated on concentric spheres. We derive analytical expressions for the coverage probability, which take into account the in-cluster geometry of the coordinated satellite set. These expressions are formulated in terms of various parameters, including the number of antennas per satellite, satellite density, fading characteristics, and path-loss exponent. To offer a more intuitive understanding, we also develop an approximation for the coverage probability. Furthermore, by considering the distribution of normalized distances, we derive the spatially averaged coverage probability, thereby validating the advantages of coordinated beamforming from a spatial average perspective. Our primary finding is that dynamic coordinated beamforming significantly improves coverage compared to the absence of satellite coordination, in direct proportion to the number of antennas on each satellite. Moreover, we observe that the optimal cluster size, which maximizes the ergodic spectral efficiency, increases with higher satellite density, provided that the number of antennas on the satellites is sufficiently large. Our findings are corroborated by simulation results, confirming the accuracy of the derived expressions.