TY - JOUR
T1 - Joint Optimization of Beamforming, Phase-Shifting and Power Allocation in a Multi-Cluster IRS-NOMA Network
AU - Xie, Ximing
AU - Fang, Fang
AU - Ding, Zhiguo
N1 - Funding Information:
Manuscript received March 2, 2021; revised May 7, 2021 and June 2, 2021; accepted June 3, 2021. Date of publication June 17, 2021; date of current version August 13, 2021. This work was supported in part by the U.K. EPSRC under Grant EP/P009719/2 and in part by H2020-MSCA-RISE-2015 under Grant 690750. The review of this article was coordinated by Dr. Khoa Le. (Corresponding author: Ximing Xie).
Publisher Copyright:
© 1967-2012 IEEE.
PY - 2021/8
Y1 - 2021/8
N2 - The combination of non-orthogonal multiple access (NOMA) and intelligent reflecting surface (IRS) is an efficient solution to significantly enhance the energy efficiency of the wireless communication system. In this paper, a downlink multi-cluster NOMA network is considered, where each cluster is supported by one IRS. This paper aims to minimize the transmit power by jointly optimizing the beamforming, the power allocation and the phase shift of each IRS. The formulated problem is non-convex and challenging to be solved due to the coupled variables, i.e., the beamforming vector, the power allocation coefficient and the phase shift matrix. To address this non-convex problem, an alternating optimization based algorithm is proposed. Specifically, the primal problem is divided into two subproblems for beamforming optimization and phase shifting feasiblity, where the two subproblems are solved iteratively. Moreover, to guarantee the feasibility of the beamforming optimization problem, an iterative algorithm is proposed to search the feasible initial points. To reduce the complexity, a simplified algorithm based on partial exhaustive search for this system model is also proposed. Simulation results demonstrate that the proposed alternating algorithm can yield a better performance gain than the partial exhaustive search algorithm, NOMA with random IRS phase shift scheme and OMA-IRS scheme.
AB - The combination of non-orthogonal multiple access (NOMA) and intelligent reflecting surface (IRS) is an efficient solution to significantly enhance the energy efficiency of the wireless communication system. In this paper, a downlink multi-cluster NOMA network is considered, where each cluster is supported by one IRS. This paper aims to minimize the transmit power by jointly optimizing the beamforming, the power allocation and the phase shift of each IRS. The formulated problem is non-convex and challenging to be solved due to the coupled variables, i.e., the beamforming vector, the power allocation coefficient and the phase shift matrix. To address this non-convex problem, an alternating optimization based algorithm is proposed. Specifically, the primal problem is divided into two subproblems for beamforming optimization and phase shifting feasiblity, where the two subproblems are solved iteratively. Moreover, to guarantee the feasibility of the beamforming optimization problem, an iterative algorithm is proposed to search the feasible initial points. To reduce the complexity, a simplified algorithm based on partial exhaustive search for this system model is also proposed. Simulation results demonstrate that the proposed alternating algorithm can yield a better performance gain than the partial exhaustive search algorithm, NOMA with random IRS phase shift scheme and OMA-IRS scheme.
KW - Intelligent reflective surface (IRS)
KW - non-orthogonal multiple access (NOMA)
KW - transmit power optimization
UR - https://www.scopus.com/pages/publications/85112150253
U2 - 10.1109/TVT.2021.3090255
DO - 10.1109/TVT.2021.3090255
M3 - Article
AN - SCOPUS:85112150253
SN - 0018-9545
VL - 70
SP - 7705
EP - 7717
JO - IEEE Transactions on Vehicular Technology
JF - IEEE Transactions on Vehicular Technology
IS - 8
M1 - 9459531
ER -
