Channel Estimation for Delay Alignment Modulation

TL;DR

This paper proposes an efficient channel estimation method for Delay Alignment Modulation (DAM) using block orthogonal matching pursuit, enabling ISI-free communication with low training overhead and performance close to perfect CSI.

Contribution

It introduces a BOMP-based channel estimation technique tailored for DAM, addressing the practical challenge of acquiring CSI efficiently.

Findings

BOMP effectively estimates CSI with low training overhead.

DAM performance with estimated CSI approaches that with perfect CSI.

Simulation confirms the viability of the proposed estimation method.

Abstract

Delay alignment modulation (DAM) is a promising technology for inter-symbol interference (ISI)-free communication without relying on sophisticated channel equalization or multi-carrier transmissions. The key ideas of DAM are delay precompensation and path-based beamforming, so that the multi-path signal components will arrive at the receiver simultaneously and constructively, rather than causing the detrimental ISI. However, the practical implementation of DAM requires channel state information (CSI) at the transmitter side. Therefore, in this letter, we study an efficient channel estimation method for DAM based on block orthogonal matching pursuit (BOMP) algorithm, by exploiting the block sparsity of the channel vector. Based on the imperfectly estimated CSI, the delay pre-compensations and tap-based beamforming are designed for DAM, and the resulting performance is studied. Simulation results demonstrate that with the BOMP-based channel estimation method, the CSI can be effectively acquired with low training overhead, and the performance of DAM based on estimated CSI is comparable to the ideal case with perfect CSI.