Time-Domain Multi-Beam Selection and Its Performance Improvement for mmWave Systems

TL;DR

This paper proposes a time-domain multi-beam selection method for mmWave systems that enhances observation quality and beam selection accuracy by exploiting the sparsity of channel impulse responses in the time domain.

Contribution

It introduces a novel approach that uses time-domain properties and deconvolution to improve beam selection performance in frequency-selective fading channels.

Findings

Enhanced beam selection accuracy at low SNR.

Reduced size of Toeplitz matrix in deconvolution.

Refined observations lead to better multipath delay estimation.

Abstract

Multi-beam selection is one of the crucial technologies in hybrid beamforming systems for frequency-selective fading channels. Addressing the problem in the frequency domain facilitates the procedure of acquiring observations for analog beam selection. However, it is difficult to improve the quality of the contaminated observations at low SNR. To this end, this paper uses an idea that the significant observations are sparse in the time domain to further enhance the quality of signals as well as the beam selection performance. By exploiting properties of channel impulse responses and circular convolutions in the time domain, we can reduce the size of a Toeplitz matrix in deconvolution to generate periodic true values of coupling coefficients plus random noise signals. An arithmetic mean of these signals yields refined observations with minor noise effects and provides more accurate sparse multipath delay information. As a result, only the refined observations associated with the estimated multipath delay indices have to be taken into account for the analog beam selection problem.