论文标题
Nakagami-M频道中的RIS辅助合作FD-SWIPT-NOMA中断性能
RIS-aided Cooperative FD-SWIPT-NOMA Outage Performance in Nakagami-m Channels
论文作者
论文摘要
在这项工作中，我们研究了可重构的智能表面（RIS）辅助合作的非正交多访问（C-NOMA），由两个配对用户组成，其中RIS的相位配置为增强细胞中心设备。细胞中心设备被指定为充电（FD）继电器，以协助细胞边缘设备。细胞中心设备不利用其电池能量进行配合，而是使用同时无线信息传递（SWIPT）收集能量。考虑了更实用的非线性能量收集模型。假设所有用户的链接都经历了Nakagamii- $ m $ channel vading，则设计了停电概率（OP）和厄贡率（ER）的表达式（ER）。我们首先通过匹配技术将收获的功率近似为伽马随机变量。这使我们能够得出易于计算的分析性操作表达式，这些表达式对于广泛的RIS被动元件配置，能量收集（EH）系数和残留的自我干扰（SI）水平，通过数值模拟广泛验证。 OP表达式揭示了在FD继电器模式下减轻SI的最重要意义，因为对于剩余Si系数的合理值（$ω\ geq -20 $ db），它对系统性能的有害效果值得注意。同样，数值结果表明，增加RIS元素的数量可以使合作系统受益于非合作性系统。
In this work, we investigate reconfigurable intelligent surfaces (RIS)-assisted cooperative non-orthogonal multiple access (C-NOMA) consisting of two paired users, where the phases of RIS are configured to boost the cell-center device. The cell-center device is designated to act as a full-duplex (FD) relay to assist the cell-edge device. The cell-center device does not use its battery energy to cooperate but harvests energy using simultaneous wireless information power transfer (SWIPT). A more practical non-linear energy harvesting model is considered. Expressions for outage probability (OP) and ergodic rate (ER) are devised, assuming that all users' links undergo Nakagami-$m$ channel fading. We first approximate the harvested power as Gamma random variables via the moments matching technique. This allows us to derive analytical OP/ER expressions that are simple to compute yet accurate for a wide range of RIS passive elements configurations, energy harvesting (EH) coefficients, and residual self-interference (SI) levels, being extensively validated by numerical simulations. The OP expressions reveal how paramount is to mitigate the SI in the FD relay mode since for reasonable values of residual SI coefficient ($ω\geq -20$dB), it is notable its detrimental effect on the system performance. Also, numerical results reveal that increasing the number of RIS elements can benefit the cooperative system more than the non-cooperative one.
