| 摘要: |
| 为解决可重构智能表面（Reconfigurable Intelligent Surface，RIS）辅助下行多载波非正交多址接入（Non-orthogonal Multiple Access，NOMA）系统中用户公平性问题，提出了一种基于RIS分区的有效解决方案，用户间使用NOMA技术进行通信，旨在提高所有用户的通信质量。为此，构建最大-最小用户可达通信速率优化问题。由于该问题中的子载波分配、无线接入点功率分配与RIS分区在用户速率处高度耦合，是一个混合整数非线性规划问题，因此提出一种基于联合优化的低复杂度求解算法，首先将原问题解耦为一个非凸问题与一个匹配问题，再利用从非凸问题中获得的解将原始问题重新表述为离散聚类问题。仿真结果证明，当系统发射功率小于32 dBm或RIS反射单元个数小于25时，所提系统相较于现有RIS相移优化方案可获得0.03~1.08 b/s/Hz的系统最小用户速率增益，相较于现有匹配算法可获得0.06~0.16 b/s/Hz的系统最小用户速率增益。 |
| 关键词: 非正交多址接入（NOMA） 可重构智能表面(RIS) 公平性优化 联合优化 |
| DOI：10.20079/j.issn.1001-893x.250116003 |
|
| 基金项目:国家自然科学基金资助项目（62271368，62371367）；中央高校基本科研业务费（QTZX23066）； 陕西省重点研发计划（2023-ZDLGY-50） |
|
| Fairness Optimization for Partition RIS-assisted NOMA System |
| GAO Yiqi,CHEN Jian,LYU Lu,YANG Long |
| (School of Telecommunications Engineering，Xidian University，Xi’an 710071，China) |
| Abstract: |
| To solve the user fairness challenge in reconfigurable intelligent surface(RIS)-assisted downlink multicarrier non-orthogonal multiple access(NOMA) systems，an effective solution based on RIS partitioning is proposed，where users communicate with each other using NOMA techniques to enhance the communication quality for all users.Specifically，a maximum-minimum user achievable rate optimization problem is formulated，which is a mixed-integer nonlinear programming problem due to the high coupling of subcarrier allocation，access point(AP) power allocation，and RIS partitioning.To tackle the complexity，a low-complexity joint optimization algorithm is introduced.The approach first decouples the original problem into a nonconvex optimization problem and a matching problem.Subsequently，the original problem is reformulated into a discrete clustering problem using the solution derived from the nonconvex problem.The simulation results show that when the system transmit power is below 32 dBm or the number of RIS reflecting elements is fewer than 25，the proposed system achieves a minimum user rate gain of 0.03~1.08 b/s/Hz over existing RIS phase shift optimization schemes and 0.06~0.16 b/s/Hz over conventional matching-based algorithms. |
| Key words: non-orthogonal multiple access(NOMA) reconfigurable intelligent surface(RIS) fairness optimization joint optimization |
《电讯技术》编辑部 