Delay Alignment Modulation with Hybrid beamforming for Spatially Sparse Communications

TL;DR

This paper introduces a hybrid beamforming approach for delay alignment modulation in mmWave/THz communications, reducing hardware costs while maintaining high performance in spatially sparse channels.

Contribution

It proposes a hybrid analog/digital beamforming design for DAM, enabling near-digital performance with fewer RF chains in massive MIMO systems.

Findings

Hybrid beamforming achieves performance close to fully digital DAM.

Simulation results confirm effectiveness in mmWave/THz channels.

Reduces hardware cost and power consumption.

Abstract

For millimeter wave (mmWave) or Terahertz (THz) communications, by leveraging the high spatial resolution offered by large antenna arrays and the multi-path sparsity of mmWave/THz channels, a novel inter-symbol interference (ISI) mitigation technique called delay alignment modulation (DAM) has been recently proposed. The key ideas of DAM are delay pre-compensation and path-based beamforming. However, existing research on DAM is based on fully digital beamforming, where the number of radio frequency (RF) chains required is equal to the number of antennas. This leads to high hardware cost and power consumption for mmWave/THz massive multiple-input multiple-output (MIMO) communications. Thus, this paper proposes the hybrid analog/digital beamforming based DAM. The analog and digital beamforming matrices are designed to achieve performance close to DAM based on fully digital beamforming. The effectiveness of the proposed technique is verified by simulation results.