A Low-Complexity Approach for Max-Min Fairness in Uplink Cell-Free Massive MIMO

Muhammad Farooq, Hien-Quoc Ngo, Le Nam Tran

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


We consider the problem of max-min fairness for uplink cell-free massive multiple-input multiple-output which is a potential technology for beyond 5G networks. More specifically, we aim to maximize the minimum spectral efficiency of all users subject to the per-user power constraint, assuming linear receive combining technique at access points. The considered problem can be further divided into two subproblems: the receiver filter coefficient design and the power control problem. While the receiver coefficient design turns out to be a generalized eigenvalue problem, and thus, admits a closed-form solution, the power control problem is numerically troublesome. To solve the power control problem, existing approaches rely on geometric programming (GP) which is not suitable for large-scale systems. To overcome the high-complexity issue of the GP method, we first reformulate the power control problem intro a convex program, and then apply a smoothing technique in combination with an accelerated projected gradient method to solve it. The simulation results demonstrate that the proposed solution can achieve almost the same objective but in much lesser time than the existing GP-based method.
Original languageEnglish
Title of host publication2021 IEEE Vehicular Technology Conference (VTC20021-Spring): Proceedings
PublisherInstitute of Electrical and Electronics Engineers Inc.
ISBN (Electronic)9781728189642
Publication statusPublished - 15 Jun 2021
Event93rd IEEE Vehicular Technology Conference, VTC 2021-Spring - Virtual, Online
Duration: 25 Apr 202128 Apr 2021

Publication series

NameIEEE Vehicular Technology Conference
ISSN (Print)1550-2252


Conference93rd IEEE Vehicular Technology Conference, VTC 2021-Spring
CityVirtual, Online

Bibliographical note

Funding Information:
This publication has emanated from research supported by a Grant from Science Foundation Ireland under Grant number 17/CDA/4786 APPENDIX In this appendix, we show that the complexity of computing uk is O(KM2). Without loss of generality, let us consider the inverse of Bk for user 1. It is obvious that we can write B1−1 as

Publisher Copyright:
© 2021 IEEE.


  • Cell-free massive MIMO
  • gradient
  • max-min fairness
  • power-control

ASJC Scopus subject areas

  • Computer Science Applications
  • Electrical and Electronic Engineering
  • Applied Mathematics


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