Resource Allocation for Two-Tier RIS-Assisted Heterogeneous NOMA Networks

• 作者: XU Yongjun YANG Zhaohui HUANG Chongwen YUEN Chau GUI Guan
• 来源期刊: 中兴通讯技术（英文版）
• 年，卷（期）: 2022,（1）
• 所属期刊栏目: Special Topic
• 页码范围: 36-47
• 页数: 12页
• 语种: 英文
• DOI: 10.12142/ZTECOM.202201006

摘要

Reconfigurable intelligent surface (RIS) as a promising technology has been proposed to change weak communication environ-ments. However, most of the current resource allocation (RA) schemes have focused on RIS-assisted homogeneous networks, and there is still no open works about RA schemes of RIS-assisted heterogeneous networks (HetNets). In this paper, we design an RA scheme for a RIS-assisted HetNet with non-orthogonal multiple access to improve spectrum efficiency and transmission rates. In particular, we jointly optimize the transmit power of the small-cell base station and the phase-shift matrix of the RIS to maximize the sum rates of all small-cell users, subject to the unit modulus constraint, the minimum signal-to-interference-plus-noise ratio constraint, and the cross-tier interference constraint for protecting communication quality of microcell users. An efficient suboptimal RA scheme is proposed based on the alternating iteration ap-proach, and successive convex approximation and logarithmic transformation approach. Simulation results verify the effectiveness of the pro-posed scheme in terms of data rates.