Tampere University of Technology

TUTCRIS Research Portal

Digital Predistortion for Multiuser Hybrid MIMO at mmWaves

Research output: Contribution to journalArticleScientificpeer-review

Details

Original languageEnglish
Pages (from-to)3603-3618
Number of pages16
JournalIEEE Transactions on Signal Processing
Volume68
DOIs
Publication statusPublished - 2020
Publication typeA1 Journal article-refereed

Abstract

Efficient mitigation of power amplifier (PA) nonlinear distortion in multi-user hybrid precoding based broadband mmWave systems is an open research problem. In this article, we carry out detailed signal and distortion modeling in broadband multi-user hybrid MIMO systems, with a bank of nonlinear PAs in each subarray, while also take the inevitable crosstalk between the antenna/PA branches into account. Building on the derived models, we adopt and describe an efficient closed-loop (CL) digital predistortion (DPD) solution that utilizes only a single-input DPD unit per transmit chain or subarray, despite crosstalk, providing thus substantial complexity-benefit compared to the state-of-the art multi-dimensional DPD solutions. We show that under spatially correlated multipath propagation, each single-input DPD unit can provide linearization towards every intended user, or more generally, towards all spatial directions where coherent propagation is taking place, and that the adopted CL DPD system is robust against crosstalk. Extensive numerical results building on practical measurement-based mmWave PA models are provided, demonstrating and verifying the excellent linearization performance of the overall DPD system in different evaluation scenarios.

Keywords

  • Crosstalk, digital predistortion, hybrid MIMO, large-array transmitters, millimeter wave communications, multi-user MIMO, nonlinear distortion, out-of-band emissions, power amplifiers

Publication forum classification