Wideband Channel Estimation for Hybrid Beamforming Millimeter Wave Communication Systems with Low-Resolution ADCs

TL;DR

This paper evaluates channel estimation algorithms for wideband millimeter wave systems with hybrid beamforming and low-resolution ADCs, highlighting the trade-offs between quantization levels, RF chains, and estimation accuracy.

Contribution

It provides a comparative analysis of channel estimation performance using various ADC resolutions and algorithms in hybrid beamforming mmWave systems, revealing counterintuitive insights.

Findings

One-bit ADCs with OMP outperform infinite-bit ADCs with least-squares in certain SNR ranges.

Three- and four-bit quantizers nearly match unquantized performance with OMP.

Single RF chain can outperform multiple RF chains with enough frames.

Abstract

A potential tremendous spectrum resource makes millimeter wave (mmWave) communications a promising technology. High power consumption due to a large number of antennas and analog-to-digital converters (ADCs) for beamforming to overcome the large propagation losses is problematic in practice. As a hybrid beamforming architecture and low-resolution ADCs are considered to reduce power consumption, estimation of mmWave channels becomes challenging. We evaluate several channel estimation algorithms for wideband mmWave systems with hybrid beamforming and low-resolution ADCs. Through simulation, we show that 1) infinite bit ADCs with least-squares estimation have worse channel estimation performance than do one-bit ADCs with orthogonal matching pursuit (OMP) in an SNR range of interest, 2) three- and four-bit quantizers can achieve channel estimation performance close to the unquantized case when using OMP, 3) a receiver with a single RF chain can yield better estimates than that with four RF chains if enough frames are exploited, and 4) for one-bit ADCs, exploitation of higher transmit power and more frames for performance enhancement adversely affects estimation performance after a certain point.