On the Energy Efficiency Maximization of NOMA-Aided Downlink Networks With Dynamic User Pairing

IEEE Access

Oh-Soon Shin¹  Hieu V. Nguyen²  Kha-Hung Nguyen²  Luca Sanguinetti³  Mai T. P. Le⁴ 

[1] Informazione, University of Pisa, Pisa, Italy;Department of ICMC Convergence Technology, School of Electronic Engineering, Soongsil University, Seoul, South Korea;Dipartimento di Ingegneria dell&x2019;Faculty of Electronics and Telecommunication Engineering, The University of Danang - University of Science and Technology, Da Nang, Vietnam;

关键词: Beamforming;    non-orthogonal multiple access (NOMA);    convex optimization;    user pairing;    energy efficiency;    robust design;   

DOI  :  10.1109/ACCESS.2022.3162875

来源: DOAJ

【 摘 要 】

This study investigates a combined system comprising non-orthogonal multiple access (NOMA) and beamforming in a downlink network. To fully exploit the advantages of NOMA, user (UE) pairing and beamforming design are jointly optimized via a generalized model for UE association, subject to energy efficiency maximization. Owing to the combination of binary variables and nonconvex constraints, the resulting optimization problem belongs to the class of mixed-integer nonconvex programming. An innovative algorithm, integrating the inner-approximation and Dinkelbach methods, is proposed herein to address a nonconvex fractional function. By introducing a pairing matrix and relaxing the binary variables into continuous ones, our approach is capable of reaching an optimal solution, where two arbitrary UEs are optimally paired regardless of geographical or spatial constraints. For practical scenarios, we further propose a robust design to manage the effect of channel estimation errors under settings involving channel uncertainty. Numerical results show that our proposed designs, even with the presence of the imperfect channel state information at the base station, significantly outperform the conventional beamforming and existing pairing schemes.

【 授权许可】

Unknown