Iteratively Weighted MMSE Uplink Precoding for Cell-Free Massive MIMO

Zhe Wang, Jiayi Zhang, Hien Quoc Ngo, Bo Ai, Merouane Debbah

Research output: Chapter in Book/Report/Conference proceedingConference contribution


In this paper, we investigate a cell-free massive MIMO system with both access points and user equipments equipped with multiple antennas over the Weichselberger Rayleigh fading channel. We study the uplink spectral efficiency (SE) based on a two-layer decoding structure with maximum ratio (MR) or local minimum mean-square error (MMSE) combining applied in the first layer and optimal large-scale fading decoding method implemented in the second layer, respectively. To maximize the weighted sum SE, an uplink precoding structure based on an Iteratively Weighted sum-MMSE (I-WMMSE) algorithm using only channel statistics is proposed. Furthermore, with MR combining applied in the first layer, we derive novel achievable SE expressions and optimal precoding structures in closed-form. Numerical results validate our proposed results and show that the I-WMMSE precoding can achieve excellent sum SE performance.

Original languageEnglish
Title of host publicationICC 2022: IEEE International Conference on Communications
PublisherInstitute of Electrical and Electronics Engineers Inc.
Number of pages6
ISBN (Electronic)9781538683477
Publication statusPublished - 11 Aug 2022
EventIEEE International Conference on Communications - Seoul, Korea, Republic of
Duration: 16 May 202220 May 2022

Publication series

NameIEEE International Conference on Communications
ISSN (Print)1550-3607
ISSN (Electronic)1938-1883


ConferenceIEEE International Conference on Communications
Abbreviated titleICC
Country/TerritoryKorea, Republic of
Internet address

Bibliographical note

Funding Information:
This work was supported in part by National Key R&D Program of China under Grant 2020YFB1807201, in part by National Natural Science Foundation of China under Grants 61971027, and 61961130391, in part by Beijing Natural Science Foundation under Grant L202013, in part by Natural Science Foundation of Jiangsu Province, Major Project under Grant BK20212002, in part by the Royal Society Newton Advanced Fellowship under Grant NA191006, in part by Frontiers Science Center for Smart High-speed Railway System.

Publisher Copyright:
© 2022 IEEE.

ASJC Scopus subject areas

  • Computer Networks and Communications
  • Electrical and Electronic Engineering


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