论文标题
智能反射表面辅助诺玛系统的资源分配
Resource Allocation in Intelligent Reflecting Surface Assisted NOMA Systems
论文作者
论文摘要
本文研究了智能反射表面（IRS）辅助非正交多访问（NOMA）系统的下行链路通信。为了最大程度地提高系统吞吐量，我们在通道分配，NOMA用户的解码，电源分配和反射系数上提出了一个联合优化问题。事实证明，该法式问题是NP-HARD。为了解决这个问题，提出了一种三步的新型资源分配算法。首先，通过多对一匹配算法解决了通道分配问题。其次，通过考虑IRS反射系数设计，提出了低复杂性解码阶优化算法。第三，给定通道分配和解码顺序，提出了一种联合优化算法来解决关节功率分配和反射系数设计问题。数值结果表明：i）借助IRS，提议的IRS-NOMA系统在没有IRS的系统吞吐量方面优于常规NOMA系统； ii）拟议的IRS-NOMA系统比IRS协助正交多重访问（IRS-SOMA）系统获得更高的系统吞吐量； iii）模拟结果表明，可以通过仔细选择IRS的位置来增强IRS-NOMA和IRS-homa系统的性能增长。
This paper investigates the downlink communications of intelligent reflecting surface (IRS) assisted non-orthogonal multiple access (NOMA) systems. To maximize the system throughput, we formulate a joint optimization problem over the channel assignment, decoding order of NOMA users, power allocation, and reflection coefficients. The formulated problem is proved to be NP-hard. To tackle this problem, a three-step novel resource allocation algorithm is proposed. Firstly, the channel assignment problem is solved by a many-to-one matching algorithm. Secondly, by considering the IRS reflection coefficients design, a low-complexity decoding order optimization algorithm is proposed. Thirdly, given a channel assignment and decoding order, a joint optimization algorithm is proposed for solving the joint power allocation and reflection coefficient design problem. Numerical results illustrate that: i) with the aid of IRS, the proposed IRS-NOMA system outperforms the conventional NOMA system without the IRS in terms of system throughput; ii) the proposed IRS-NOMA system achieves higher system throughput than the IRS assisted orthogonal multiple access (IRS-OMA) systems; iii) simulation results show that the performance gains of the IRS-NOMA and the IRS-OMA systems can be enhanced via carefully choosing the location of the IRS.
