In this paper, we propose a novel reconfigurable intelligent surface (RIS)-based modulation scheme, named RIS-aided receive quadrature reflecting modulation (RIS-RQRM), by resorting to the concept of spatial modulation. In RIS-RQRM, the whole RIS is virtually partitioned into two halves to create signals with only in-phase (I-) and quadrature (Q-) components, respectively, and each half forms a beam to a receive antenna whose index carries the bit information. Furthermore, we design a low-complexity and non-coherent detector for RIS-RQRM, which measures the maximum power and polarities of the I- and Q- components of received signals. Approximate bit error rate (BER) expressions are derived for RIS-RQRM over Rician fading channels. Simulation results show that RIS-RQRM outperforms the existing counterparts without I/Q index modulation in terms of BER in the low signal-to-noise ratio region.

中文翻译：

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接收正交反射调制以实现 RIS 赋能的无线通信


在本文中，我们利用空间调制的概念，提出了一种新颖的基于可重构智能表面（RIS）的调制方案，称为RIS辅助接收正交反射调制（RIS-RQRM）。在 RIS-RQRM 中，整个 RIS 实际上被分为两半，分别产生仅具有同相 (I-) 和正交 (Q-) 分量的信号，每一半形成一个波束，到达接收天线，其索引携带位信息。此外，我们为 RIS-RQRM 设计了一种低复杂度和非相干检测器，用于测量接收信号的 I 和 Q 分量的最大功率和极性。近似误码率 (BER) 表达式是针对莱斯衰落信道上的 RIS-RQRM 得出的。仿真结果表明，在低信噪比区域的 BER 方面，RIS-RQRM 优于现有的没有 I/Q 指数调制的同类产品。