Quasisynchronous LoRa for LEO Nanosatellite Communications

TL;DR

This paper investigates quasisynchronous LoRa communication for LEO satellites, addressing synchronization challenges and analyzing SER performance over AWGN channels to support IoT and global connectivity.

Contribution

It introduces the concept of quasisynchronous LoRa for LEO satellites and studies its SER performance with different waveforms and spreading factors, a novel approach in this context.

Findings

Quasisynchronous LoRa improves communication reliability and resource efficiency.

SER performance varies with spreading factors and waveform types.

The study provides insights into synchronization trade-offs for satellite IoT applications.

Abstract

Perfect synchronization in LoRa communications between Low Earth Orbit (LEO) satellites and ground base stations is still challenging, despite the potential use of atomic clocks in LEO satellites, which offer high precision. Even by incorporating atomic clocks in LEO satellites, their inherent precision can be leveraged to enhance the overall synchronization process, perfect synchronization is infeasible due to a combination of factors such as signal propagation delay, Doppler effects, clock drift and atmospheric effects. These challenges require the development of advanced synchronization techniques and algorithms to mitigate their effects and ensure reliable communication from / to LEO satellites. However, maintaining acceptable levels of synchronization rather than striving for perfection, quasisynchronous (QS) communication can be adopted which maintains communication reliability, improves resource utilization, reduces power consumption, and ensures scalability as more devices join the communication. Overall, QS communication offers a practical, adaptive, and robust solution that enables LEO satellite communications to support the growing demands of IoT applications and global connectivity. In our investigation, we explore different chip waveforms such as rectangular and raised cosine. Furthermore, for the first time, we study the Symbol Error Rate (SER) performance of QS LoRa communication, for different spreading factors (SF), over Additive White Gaussian Noise (AWGN) channels.