Reconfigurable Intelligent Surface-Aided NOMA with Limited Feedback
Reconfigurable Intelligent Surface-Aided NOMA with Limited Feedback
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DOI：
10.1109/icc45041.2023.10279591
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发表时间：
2023-01
期刊：
影响因子：
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通讯作者：
Mojtaba Ahmadi Almasi;H. Jafarkhani
中科院分区：
文献类型：
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作者：
Mojtaba Ahmadi Almasi;H. Jafarkhani
由于可用的反馈位有限，因此频分式双工（FDD）系统中反馈通道的设计是一个主要挑战。我们考虑包含可重构智能表面（RISS）的非正交多访问（NOMA）系统。在有限的反馈RIS辅助NOMA系统中，应对RIS AD的通道和直接通道的增益进行量化并馈回发射器。本文调查了患有量化错误的总RIS辅助NOMA系统的速率损失。我们首先考虑RIS AID通道的随机矢量量化和直接通道增益的相同均匀量化器。然后，由于量化误差，我们获得了速率损失的上限，这是反馈位数和RIS大小的函数。我们的数值结果表明，随着反馈位的数量的增加，有限反馈系统的总和率性能是使用完整CSI的系统的方法。
The design of feedback channels in frequency division duplex (FDD) systems is a major challenge because of the limited available feedback bits. We consider non-orthogonal multiple access (NOMA) systems that incorporate reconfigurable intelligent surfaces (RISs). In limited feedback RIS-aided NOMA systems, the RIS-aided channel and the direct channel gains should be quantized and fed back to the transmitter. This paper investigates the rate loss of the overall RIS-aided NOMA systems suffering from quantization errors. We first consider random vector quantization for the overall RIS-aided channel and identical uniform quantizers for the direct channel gains. We then obtain an upper bound for the rate loss, due to the quantization error, as a function of the number of feedback bits and the size of RIS. Our numerical results indicate the sum rate performance of the limited feedback system approaches that of the system with full CSI as the number of feedback bits increases.