Location-assisted precoding in 5G LEO systems: architectures and performances

TL;DR

This paper investigates position-based precoding schemes for 5G LEO satellite systems, analyzing their performance and proposing architectures that account for satellite and user mobility, aiming to enhance throughput with limited CSI.

Contribution

It introduces and evaluates two position-aware precoding architectures for 5G LEO satellites, considering satellite and user mobility, and compares their performance to optimal solutions.

Findings

Position-based precoding schemes perform close to optimal MMSE.

Two system architectures effectively incorporate satellite and user movement.

Numerical results demonstrate the viability of the proposed schemes.

Abstract

Satellite communication systems are a fundamental component in support of Europe's ambition to deploy smart and sustainable networks and services for the success of its digital economy. To cope with the 5G and beyond ever increasing demand for larger throughput, aggressive frequency reuse schemes (i.e., full frequency reuse), with the implementation of precoding/beamforming to cope with the massive co-channel interference, are recognised as one of the key technologies. While the best performance can be obtained with the knowledge of the Channel State Information (CSI) at the transmitter, this also poses some technical challenges related to signalling and synchronisation. In this paper, we focus on precoding solutions that only needs the knowledge of the users' positions at the transmitter side, namely the recently introduced Switchable Multi-Beam (MB) and Spatially Sampled MMSE (SS-MMSE) precoding. Compared to the vast majority of the studies in the literature, we take into account both the users' and the satellite movement in a Low Earth Orbit (LEO) mega-constellation, also proposing two system architectures. The extensive numerical assessment provides a valuable insight on the performance of these two precoding schemes compared to the optimal MMSE solution.