Affine Frequency Division Multiplexing For Communications on Sparse Time-Varying Channels

TL;DR

This paper demonstrates that Affine Frequency Division Multiplexing (AFDM) is optimal for channel estimation in sparse, time-varying wireless channels, reducing pilot overhead compared to other waveforms through analysis and simulations.

Contribution

The paper establishes the optimality of AFDM for sparse LTV channel estimation and quantifies minimal pilot overhead needed for accurate estimation.

Findings

AFDM achieves the smallest pilot and guard overhead for target MSE.

Mathematical analysis confirms AFDM's optimality in sparse LTV channels.

Numerical results support AFDM's superior performance over conventional waveforms.

Abstract

This paper addresses channel estimation for linear time-varying (LTV) wireless propagation links under the assumption of double sparsity i.e., sparsity in both the delay and the Doppler domains. Affine frequency division multiplexing (AFDM), a recently proposed waveform, is shown to be optimal (in a sense that we make explicit) for this problem. With both mathematical analysis and numerical results, the minimal pilot and guard overhead needed for achieving a target mean squared error (MSE) while performing channel estimation is shown to be the smallest when AFDM is employed instead of both conventional and recently proposed waveforms.