论文标题
智能反射表面有助于褪色通道多次访问
Intelligent Reflecting Surface Aided Multiple Access Over Fading Channels
论文作者
论文摘要
本文考虑了智能反射表面（IRS）辅助网络的两用户下行链路传输在褪色的频道上。特别是，研究了非正交的多重访问（NOMA）和两个正交多访问（OMA）方案，即时间划分多重访问（TDMA）和频分部多访问（FDMA）。目的是最大化延迟耐受传输的系统平均总和率。我们提出了两个调整方案，即动态相调整和一次性相调整。电力预算，最低平均数据速率和离散单位模量反射系数被视为约束。为了解决该问题，提出了两个具有低复杂性的调整算法以获得接近最佳的解决方案。在给定的相变和时间间隔条件的满意度下，使用拉格朗日双重分解获得了最佳资源分配。数值结果表明：i）IRS提出的NOMA网络的平均总和率优于褪色通道的常规NOMA网络； ii）随着褪色块的连续IRS调整，提出的TDMA方案的性能优于FDMA方案； iii）增加最低平均用户率需求对拟议的IRS-NOMA系统的影响较小，而不是对IRS-homa系统的影响。
This paper considers a two-user downlink transmission in intelligent reflecting surface (IRS) aided network over fading channels. Particularly, non-orthogonal multiple access (NOMA) and two orthogonal multiple access (OMA) schemes, namely, time division multiple access (TDMA) and frequency division multiple access (FDMA), are studied. The objective is to maximize the system average sum rate for the delay-tolerant transmission. We propose two adjustment schemes, namely, dynamic phase adjustment and one-time phase adjustment. The power budget, minimum average data rate, and discrete unit modulus reflection coefficient are considered as constrains. To solve the problem, two phase shifters adjustment algorithms with low complexity are proposed to obtain near optimal solutions. With given phase shifters and satisfaction of time-sharing condition, the optimal resource allocations are obtained using the Lagrangian dual decomposition. The numerical results reveal that: i) the average sum rate of proposed NOMA network aided by IRS outperforms the conventional NOMA network over fading channels; ii) with continuous IRS adjustment in the fading block, the proposed TDMA scheme performs better than the FDMA scheme; iii) increasing the minimum average user rate requirement has less impact on the proposed IRS-NOMA system than on the IRS-OMA system.
