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Efficient downlink power allocation algorithms for cell-free massive mimo systems

Chakraborty, Sucharita ; Demir, Ozlem Tugfe ; Bjornson, Emil and Giselsson, Pontus LU orcid (2021) In IEEE Open Journal of the Communications Society 2. p.168-186
Abstract

Cell-free Massive MIMO systems consist of a large number of geographically distributed access points (APs) that serve the users by coherent joint transmission. The spectral efficiency (SE) achieved by each user depends on the power allocation: which APs that transmit to which users and with what power. In this article, we revisit the max-min and sum-SE power allocation policies, which have previously been approached using high-complexity general-purpose solvers. We develop and compare several different high-performance low-complexity power allocation algorithms that are appropriate for use in large systems. We propose two new algorithms for sum-SE power optimization inspired by weighted minimum mean square error (WMMSE) minimization and... (More)

Cell-free Massive MIMO systems consist of a large number of geographically distributed access points (APs) that serve the users by coherent joint transmission. The spectral efficiency (SE) achieved by each user depends on the power allocation: which APs that transmit to which users and with what power. In this article, we revisit the max-min and sum-SE power allocation policies, which have previously been approached using high-complexity general-purpose solvers. We develop and compare several different high-performance low-complexity power allocation algorithms that are appropriate for use in large systems. We propose two new algorithms for sum-SE power optimization inspired by weighted minimum mean square error (WMMSE) minimization and fractional programming (FP). Further, one new FP-based algorithm is proposed for max-min fair power allocation. The alternating direction method of multipliers (ADMM) is used to solve specific convex subproblems in the proposed algorithms. Our ADMM reformulations lead to multiple small-sized subproblems with closed-form solutions. The proposed algorithms find global or local optimal power allocation solutions for large-scale systems but with reduced computational time compared to previous work.

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author
; ; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
ADMM, Cell-free massive MIMO, fractional programming, max-min fairness, power allocation, sum-SE maximization, WMMSE
in
IEEE Open Journal of the Communications Society
volume
2
article number
9293031
pages
19 pages
publisher
IEEE - Institute of Electrical and Electronics Engineers Inc.
external identifiers
  • scopus:85122048517
ISSN
2644-125X
DOI
10.1109/OJCOMS.2020.3044280
language
English
LU publication?
yes
additional info
Publisher Copyright: © 2020 IEEE.
id
a88aa175-dd2f-4d5f-be0c-2ee77ecc91eb
date added to LUP
2022-02-21 15:02:03
date last changed
2023-11-21 03:02:46
@article{a88aa175-dd2f-4d5f-be0c-2ee77ecc91eb,
  abstract     = {{<p>Cell-free Massive MIMO systems consist of a large number of geographically distributed access points (APs) that serve the users by coherent joint transmission. The spectral efficiency (SE) achieved by each user depends on the power allocation: which APs that transmit to which users and with what power. In this article, we revisit the max-min and sum-SE power allocation policies, which have previously been approached using high-complexity general-purpose solvers. We develop and compare several different high-performance low-complexity power allocation algorithms that are appropriate for use in large systems. We propose two new algorithms for sum-SE power optimization inspired by weighted minimum mean square error (WMMSE) minimization and fractional programming (FP). Further, one new FP-based algorithm is proposed for max-min fair power allocation. The alternating direction method of multipliers (ADMM) is used to solve specific convex subproblems in the proposed algorithms. Our ADMM reformulations lead to multiple small-sized subproblems with closed-form solutions. The proposed algorithms find global or local optimal power allocation solutions for large-scale systems but with reduced computational time compared to previous work. </p>}},
  author       = {{Chakraborty, Sucharita and Demir, Ozlem Tugfe and Bjornson, Emil and Giselsson, Pontus}},
  issn         = {{2644-125X}},
  keywords     = {{ADMM; Cell-free massive MIMO; fractional programming; max-min fairness; power allocation; sum-SE maximization; WMMSE}},
  language     = {{eng}},
  pages        = {{168--186}},
  publisher    = {{IEEE - Institute of Electrical and Electronics Engineers Inc.}},
  series       = {{IEEE Open Journal of the Communications Society}},
  title        = {{Efficient downlink power allocation algorithms for cell-free massive mimo systems}},
  url          = {{http://dx.doi.org/10.1109/OJCOMS.2020.3044280}},
  doi          = {{10.1109/OJCOMS.2020.3044280}},
  volume       = {{2}},
  year         = {{2021}},
}