Pilot Aided Channel Estimation for AFDM in Doubly Dispersive Channels

TL;DR

This paper introduces two pilot-assisted channel estimation schemes for AFDM in doubly dispersive channels, demonstrating near-ideal performance and extending to MIMO and multi-user scenarios.

Contribution

It proposes novel pilot aided channel estimation methods for AFDM and extends them to MIMO and multi-user systems, improving practical deployment.

Findings

Channel estimation with proposed schemes shows marginal performance loss.

AFDM with these schemes approaches ideal channel knowledge performance.

Extensions to MIMO and multi-user systems are feasible and effective.

Abstract

Affine frequency division multiplexing (AFDM) is a multi-chirp waveform and a promising solution for ultra-reliable communication under doubly dispersive channels. In this paper, we propose two pilot aided channel estimation schemes for AFDM, named single pilot aided (SPA) and multiple pilots aided (MPA) respectively. Pilot, guard and data symbols in the discrete affine Fourier transform (DAFT) domain are arranged appropriately at the transmitter. While at the receiver, channel estimation is performed with the aid of an estimation threshold and a mapping table. The bit error performance of AFDM applying the proposed channel estimation schemes shows only marginal loss compared to AFDM with ideally known channel state information. Moreover, extensions of the SPA scheme to multiple-input multiple-output (MIMO) and multi-user uplink/downlink are presented.