Enhancing Spectral Efficiency in STAR-RIS Aided mmWave CF mMIMO-RSMA Systems

Ridho Hendra Yoga Perdana; Toan Van Nguyen; Yushintia Pramitarini; Duy H.N. Nguyen; Daniel Benevides Da Costa; Beongku An

doi:10.1109/PIMRC62392.2025.11274631

Enhancing Spectral Efficiency in STAR-RIS Aided mmWave CF mMIMO-RSMA Systems

Ridho Hendra Yoga Perdana^*
, Toan Van Nguyen
, Yushintia Pramitarini
, Duy H.N. Nguyen
, Daniel Benevides Da Costa
, Beongku An

^*Corresponding author for this work

Interdisciplinary Research Center for Communication Systems and Sensing

Research output: Chapter in Book/Report/Conference proceeding › Conference contribution › peer-review

Abstract

This paper proposes a hybrid user group (HUG) scheme for simultaneous transmitting and reflecting-reconfigurable intelligent surface (STAR-RIS)-aided millimeter wave (mmWave) cell-free massive multiple-input multiple-output (CF mMIMO) systems using rate-splitting multiple access (RSMA), where users in transmission and reflection zones are optimally paired. Nearby APs serve users, and multiple STAR-RISs enhance signals under imperfect SIC. We formulate a max-min spectral efficiency (SE) problem to jointly optimize power allocation, STAR-RIS phase shifts, and user grouping, leading to a mixed-integer non-convex problem. To solve it, we relax discrete variables and decompose the problem into sub-problems, using bisection search for phase shifts and a low-complexity iterative algorithm for power allocation. Simulations show the HUG scheme improves average SE by 14.03%, 18.79%, and 33.42% compared to random grouping, conventional beamforming, and HUG with conventional RIS, respectively.

Original language	English
Title of host publication	2025 IEEE 36th International Symposium on Personal, Indoor and Mobile Radio Communications, PIMRC 2025
Publisher	Institute of Electrical and Electronics Engineers Inc.
ISBN (Electronic)	9798350363234
DOIs	https://doi.org/10.1109/PIMRC62392.2025.11274631
State	Published - 2025
Event	36th IEEE International Symposium on Personal, Indoor and Mobile Radio Communications, PIMRC 2025 - Istanbul, Turkey Duration: 1 Sep 2025 → 4 Sep 2025

Publication series

Name	IEEE International Symposium on Personal, Indoor and Mobile Radio Communications, PIMRC
ISSN (Print)	2166-9570
ISSN (Electronic)	2166-9589

Conference

Conference	36th IEEE International Symposium on Personal, Indoor and Mobile Radio Communications, PIMRC 2025
Country/Territory	Turkey
City	Istanbul
Period	1/09/25 → 4/09/25

Bibliographical note

Publisher Copyright:
© 2025 IEEE.

Keywords

CF mMIMO
RSMA
STAR-RIS
imperfect SIC
optimization
phase shift
spectral efficiency

ASJC Scopus subject areas

Electrical and Electronic Engineering

Access to Document

10.1109/PIMRC62392.2025.11274631

Cite this

Perdana, R. H. Y., Nguyen, T. V., Pramitarini, Y., Nguyen, D. H. N., Da Costa, D. B., & An, B. (2025). Enhancing Spectral Efficiency in STAR-RIS Aided mmWave CF mMIMO-RSMA Systems. In 2025 IEEE 36th International Symposium on Personal, Indoor and Mobile Radio Communications, PIMRC 2025 (IEEE International Symposium on Personal, Indoor and Mobile Radio Communications, PIMRC). Institute of Electrical and Electronics Engineers Inc.. https://doi.org/10.1109/PIMRC62392.2025.11274631

Perdana, Ridho Hendra Yoga ; Nguyen, Toan Van ; Pramitarini, Yushintia et al. / Enhancing Spectral Efficiency in STAR-RIS Aided mmWave CF mMIMO-RSMA Systems. 2025 IEEE 36th International Symposium on Personal, Indoor and Mobile Radio Communications, PIMRC 2025. Institute of Electrical and Electronics Engineers Inc., 2025. (IEEE International Symposium on Personal, Indoor and Mobile Radio Communications, PIMRC).

@inproceedings{a35b55d959e14314b681f9b71d202510,

title = "Enhancing Spectral Efficiency in STAR-RIS Aided mmWave CF mMIMO-RSMA Systems",

abstract = "This paper proposes a hybrid user group (HUG) scheme for simultaneous transmitting and reflecting-reconfigurable intelligent surface (STAR-RIS)-aided millimeter wave (mmWave) cell-free massive multiple-input multiple-output (CF mMIMO) systems using rate-splitting multiple access (RSMA), where users in transmission and reflection zones are optimally paired. Nearby APs serve users, and multiple STAR-RISs enhance signals under imperfect SIC. We formulate a max-min spectral efficiency (SE) problem to jointly optimize power allocation, STAR-RIS phase shifts, and user grouping, leading to a mixed-integer non-convex problem. To solve it, we relax discrete variables and decompose the problem into sub-problems, using bisection search for phase shifts and a low-complexity iterative algorithm for power allocation. Simulations show the HUG scheme improves average SE by 14.03\%, 18.79\%, and 33.42\% compared to random grouping, conventional beamforming, and HUG with conventional RIS, respectively.",

keywords = "CF mMIMO, RSMA, STAR-RIS, imperfect SIC, optimization, phase shift, spectral efficiency",

author = "Perdana, \{Ridho Hendra Yoga\} and Nguyen, \{Toan Van\} and Yushintia Pramitarini and Nguyen, \{Duy H.N.\} and \{Da Costa\}, \{Daniel Benevides\} and Beongku An",

note = "Publisher Copyright: {\textcopyright} 2025 IEEE.; 36th IEEE International Symposium on Personal, Indoor and Mobile Radio Communications, PIMRC 2025 ; Conference date: 01-09-2025 Through 04-09-2025",

year = "2025",

doi = "10.1109/PIMRC62392.2025.11274631",

language = "English",

series = "IEEE International Symposium on Personal, Indoor and Mobile Radio Communications, PIMRC",

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Perdana, RHY, Nguyen, TV, Pramitarini, Y, Nguyen, DHN, Da Costa, DB & An, B 2025, Enhancing Spectral Efficiency in STAR-RIS Aided mmWave CF mMIMO-RSMA Systems. in 2025 IEEE 36th International Symposium on Personal, Indoor and Mobile Radio Communications, PIMRC 2025. IEEE International Symposium on Personal, Indoor and Mobile Radio Communications, PIMRC, Institute of Electrical and Electronics Engineers Inc., 36th IEEE International Symposium on Personal, Indoor and Mobile Radio Communications, PIMRC 2025, Istanbul, Turkey, 1/09/25. https://doi.org/10.1109/PIMRC62392.2025.11274631

Enhancing Spectral Efficiency in STAR-RIS Aided mmWave CF mMIMO-RSMA Systems. / Perdana, Ridho Hendra Yoga; Nguyen, Toan Van; Pramitarini, Yushintia et al.
2025 IEEE 36th International Symposium on Personal, Indoor and Mobile Radio Communications, PIMRC 2025. Institute of Electrical and Electronics Engineers Inc., 2025. (IEEE International Symposium on Personal, Indoor and Mobile Radio Communications, PIMRC).

Research output: Chapter in Book/Report/Conference proceeding › Conference contribution › peer-review

TY - GEN

T1 - Enhancing Spectral Efficiency in STAR-RIS Aided mmWave CF mMIMO-RSMA Systems

AU - Perdana, Ridho Hendra Yoga

AU - Nguyen, Toan Van

AU - Pramitarini, Yushintia

AU - Nguyen, Duy H.N.

AU - Da Costa, Daniel Benevides

AU - An, Beongku

PY - 2025

Y1 - 2025

N2 - This paper proposes a hybrid user group (HUG) scheme for simultaneous transmitting and reflecting-reconfigurable intelligent surface (STAR-RIS)-aided millimeter wave (mmWave) cell-free massive multiple-input multiple-output (CF mMIMO) systems using rate-splitting multiple access (RSMA), where users in transmission and reflection zones are optimally paired. Nearby APs serve users, and multiple STAR-RISs enhance signals under imperfect SIC. We formulate a max-min spectral efficiency (SE) problem to jointly optimize power allocation, STAR-RIS phase shifts, and user grouping, leading to a mixed-integer non-convex problem. To solve it, we relax discrete variables and decompose the problem into sub-problems, using bisection search for phase shifts and a low-complexity iterative algorithm for power allocation. Simulations show the HUG scheme improves average SE by 14.03%, 18.79%, and 33.42% compared to random grouping, conventional beamforming, and HUG with conventional RIS, respectively.

AB - This paper proposes a hybrid user group (HUG) scheme for simultaneous transmitting and reflecting-reconfigurable intelligent surface (STAR-RIS)-aided millimeter wave (mmWave) cell-free massive multiple-input multiple-output (CF mMIMO) systems using rate-splitting multiple access (RSMA), where users in transmission and reflection zones are optimally paired. Nearby APs serve users, and multiple STAR-RISs enhance signals under imperfect SIC. We formulate a max-min spectral efficiency (SE) problem to jointly optimize power allocation, STAR-RIS phase shifts, and user grouping, leading to a mixed-integer non-convex problem. To solve it, we relax discrete variables and decompose the problem into sub-problems, using bisection search for phase shifts and a low-complexity iterative algorithm for power allocation. Simulations show the HUG scheme improves average SE by 14.03%, 18.79%, and 33.42% compared to random grouping, conventional beamforming, and HUG with conventional RIS, respectively.

KW - CF mMIMO

KW - RSMA

KW - STAR-RIS

KW - imperfect SIC

KW - optimization

KW - phase shift

KW - spectral efficiency

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U2 - 10.1109/PIMRC62392.2025.11274631

DO - 10.1109/PIMRC62392.2025.11274631

M3 - Conference contribution

AN - SCOPUS:105030539823

T3 - IEEE International Symposium on Personal, Indoor and Mobile Radio Communications, PIMRC

BT - 2025 IEEE 36th International Symposium on Personal, Indoor and Mobile Radio Communications, PIMRC 2025

PB - Institute of Electrical and Electronics Engineers Inc.

T2 - 36th IEEE International Symposium on Personal, Indoor and Mobile Radio Communications, PIMRC 2025

Y2 - 1 September 2025 through 4 September 2025

ER -

Perdana RHY, Nguyen TV, Pramitarini Y, Nguyen DHN, Da Costa DB, An B. Enhancing Spectral Efficiency in STAR-RIS Aided mmWave CF mMIMO-RSMA Systems. In 2025 IEEE 36th International Symposium on Personal, Indoor and Mobile Radio Communications, PIMRC 2025. Institute of Electrical and Electronics Engineers Inc. 2025. (IEEE International Symposium on Personal, Indoor and Mobile Radio Communications, PIMRC). doi: 10.1109/PIMRC62392.2025.11274631

Enhancing Spectral Efficiency in STAR-RIS Aided mmWave CF mMIMO-RSMA Systems

Abstract

Publication series

Conference

Bibliographical note

Keywords

ASJC Scopus subject areas

Access to Document

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