Robust 6G OFDM High-Mobility Communications Using Delay-Doppler Superimposed Pilots

TL;DR

This paper introduces a new receiver design for 6G high-mobility OFDM communications using delay-Doppler superimposed pilots, effectively estimating channels and maintaining performance at very high speeds.

Contribution

It presents a novel delay-Doppler superimposed pilot scheme and a fractional delay-Doppler estimation algorithm tailored for high-mobility OFDM scenarios.

Findings

Achieves robust communication at speeds up to 1000 km/h.

Improves effective throughput over existing methods.

Handles ICI, fractional delays, and Doppler shifts effectively.

Abstract

In this work, a novel receiver architecture for orthogonal frequency division multiplexing (OFDM) communications in 6G high-mobility scenarios is developed. In particular, a delay-Doppler superimposed pilot (SP) scheme is used for channel estimation (CE) by adding a single pilot in the delay-Doppler domain. Unlike previous research on delay-Doppler superimposed pilots in OFDM systems, intercarrier interference (ICI) effects, fractional delays, and Doppler shifts are considered. Consequently, a disjoint fractional delay-Doppler estimation algorithm is derived, and a reduced-complexity equalization method based on the Landweber iteration, which exploits intrinsic channel structure, is proposed. Simulation results reveal that the proposed receiver architecture achieves robust communication performance across various mobility conditions, with speeds of up to 1000 km/h, and increases the effective throughput compared to existing methods.