Harmonic Retrieval of CFO and Frame Misalignment for OFDM-based Inter-Satellite Links

TL;DR

This paper introduces a novel 2-D ESPRIT-based method for accurately estimating CFO and frame misalignment in OFDM inter-satellite links, enhancing synchronization in high-speed LEO environments.

Contribution

It presents a new estimation technique using pilot symbols and ESPRIT for joint CFO and frame misalignment estimation in OFDM satellite communications.

Findings

Achieves less than 5dB difference from state-of-the-art methods.

Derives CRLB for joint CFO and frame misalignment estimation.

Demonstrates improved synchronization accuracy in simulations.

Abstract

As dense low Earth orbit (LEO) constellations are being planned, the need for accurate synchronization schemes in high-speed environments remains a challenging problem to tackle. To further improve synchronization accuracy in channeling environments, which can also be applied in the LEO networks, we present a new method for estimating the carrier frequency offset (CFO) and frame misalignment in orthogonal frequency division multiplexing (OFDM) based inter-satellite links. The proposed method requires the transmission of pilot symbols to exploit 2-D estimation of signal parameters via rotational invariance techniques (ESPRIT) and estimate the CFO and the frame misalignment. The Cramer-Rao lower bounds (CRLB) of the joint estimation of the CFO and frame misalignment are also derived. Numerical results show that the difference between the proposed method and the state-of-art method is less than 5dB at its worse.