Gridless Channel Estimation for Mixed One-Bit Antenna Array Systems

Chang Jen Wang, Chao Kai Wen*, Shi Jin, Shang-Ho Tsai

*Corresponding author for this work

Research output: Contribution to journalArticle

7 Scopus citations

Abstract

A receiver architecture with low-resolution analog-to-digital converters (ADCs) coupled with large antenna arrays has drawn considerable interest in the millimeter wave (mm-wave) system. Although architecture with pure one-bit ADCs has low power cost, such a system presents many challenges for synchronization, channel estimation, and power level estimation. Research has been conducted recently on the so-called mixed one-bit system, in which most antennas are equipped with one-bit ADCs, and a few have high-resolution ADCs. Despite the advantages of this system, studies on how to efficiently use high-resolution outputs to aid the one-bit system are lacking. This research considers the channel estimation problem to fill this gap and proposes a two-step channel estimator by utilizing the different features of mixed outputs. The channel gain can be extracted from high-resolution ADCs, and the channel angle can be extracted by the combination of additional one-bit ADCs. The proposed estimator leverages the sparsity feature of the channel in mm-wave. In contrast to previous works that used compressive sensing techniques, which confine the estimate to the set of grid angle points and induce estimation bias, the proposed estimator is gridless and treats the angle as a continuous parameter. The simulation results demonstrate that the proposed method yields significantly lower mean square errors than the conventional maximum likelihood estimator. In addition, this paper investigates ways to further improve the channel estimate by arranging the locations of high-resolution ADCs. Several useful observations on system design are obtained through our analysis.

Original languageEnglish
Article number8515242
Pages (from-to)8485-8501
Number of pages17
JournalIEEE Transactions on Wireless Communications
Volume17
Issue number12
DOIs
StatePublished - 1 Dec 2018

Keywords

  • Channel estimation
  • compressive sensing
  • gridless
  • large-scale antenna array system
  • mixed-ADC architecture
  • one-bit ADC

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