Demonstrator Testbed for Effective Precoding in MEO Multibeam Satellites

TL;DR

This paper presents a testbed for implementing and evaluating precoding techniques in MEO satellite systems, addressing unique challenges like orbit dynamics and hardware impairments to improve broadband connectivity.

Contribution

It introduces a novel in-lab SDR-based testbed with adaptations for MEO satellite precoding, including orbit modeling and impairment mitigation strategies.

Findings

Preliminary results confirm the feasibility of the proposed precoding approach.

Synchronization loop effectively mitigates Doppler and phase noise effects.

Testbed demonstrates potential for enhancing MEO satellite broadband performance.

Abstract

The use of communication satellites in medium Earth orbit (MEO) is foreseen to provide quasi-global broadband Internet connectivity in the coming networking ecosystems. Multi-user multiple-input single-output (MU-MISO) digital signal processing techniques, such as precoding, emerge as appealing technological enablers in the forward link of multi-beam satellite systems operating in full frequency reuse (FFR). However, the orbit dynamics of MEO satellites pose additional challenges that must be carefully evaluated and addressed. This work presents the design of an in-lab testbed based on software-defined radio (SDR) platforms and the corresponding adaptations required for efficient precoding in a MEO scenario. The setup incorporates a precise orbit model and the radiation pattern of a custom-designed direct radiating array (DRA). We analyze the main impairments affecting precoding performance, including Doppler shifts and payload phase noise, and propose a synchronization loop to mitigate these effects. Preliminary experimental results validate the feasibility and effectiveness of the proposed solution.