Future Ultra-Dense LEO Satellite Networks: A Cell-Free Massive MIMO Approach

TL;DR

This paper introduces a novel cell-free massive MIMO architecture for ultra-dense LEO satellite networks, aiming to enhance connectivity, throughput, and handover management in future satellite constellations.

Contribution

It proposes the first CF-mMIMO based framework for LEO SatNets, including network design, optimization of power and handover, and demonstrates superior performance through simulations.

Findings

Enhanced network throughput with CF-mMIMO architecture

Reduced handover rate compared to traditional methods

Improved quality-of-service for users

Abstract

Low Earth orbit (LEO) satellite networks (SatNets) are envisioned to play a crucial role in providing global and ubiquitous connectivity efficiently. Accordingly, in the coming years, thousands of LEO satellites will be launched to create ultradense LEO mega-constellations, and the Third Generation Partnership Project (3GPP) is working on evolving fifth-generation (5G) systems to support such non-terrestrial networks (NTN). However, many challenges are associated with the deployment of LEOs from communications and networking perspectives. In this paper, we propose a novel cell-free massive multiple-input multiple-output (CF-mMIMO) based architecture for future ultra-dense LEO SatNets. We discuss various aspects of network design, such as duplexing mode, pilot assignment, beamforming, and handover management. In addition, we propose a joint optimization framework for the power allocation and handover management processes to maximize the network throughput and minimize the handover rate while ensuring quality-of-service (QoS) satisfaction for users. To the best of our knowledge, this is the first work to introduce and study CF-mMIMO-based LEO SatNets. Extensive simulation results demonstrate the superior performance of the proposed architecture and solutions compared to those of conventional single-satellite connectivity and handover techniques from the literature.