6G RIS-aided Single-LEO Localization with Slow and Fast Doppler Effects

TL;DR

This paper investigates the feasibility of using a single LEO satellite and a reconfigurable intelligent surface for accurate localization in 6G networks, addressing practical limitations of multi-satellite setups.

Contribution

It introduces a novel single-LEO, single-RIS localization framework with a comprehensive signal model and a low-complexity estimator achieving near-optimal performance at high SNR.

Findings

Feasibility of RIS-aided single-LEO localization demonstrated.

Proposed estimator approaches theoretical bounds at high SNR.

Model accounts for Doppler effects, CFO, and clock bias.

Abstract

6G networks aim to enable applications like autonomous driving by providing complementary localization services through key technologies such as non-terrestrial networks (NTNs) with low Earth orbit (LEO) satellites and reconfigurable intelligent surfaces (RIS). Prior research in 6G localization using single LEO, multi-LEO, and multi-LEO multi-RIS setups has limitations: single LEO lacks the required accuracy, while multi-LEO/RIS setups demand many visible satellites and RISs, which is not always feasible in practice. This paper explores the novel problem of localization with a single LEO satellite and a single RIS, bridging these research areas. We present a comprehensive signal model accounting for user carrier frequency offset (CFO), clock bias, and fast and slow Doppler effects. Additionally, we derive a low-complexity estimator that achieves theoretical bounds at high signal-to-noise ratios (SNR). Our results demonstrate the feasibility and accuracy of RIS-aided single-LEO localization in 6G networks and highlight potential research directions.