An intelligent reflecting surface (IRS) can greatly improve the channel quality over a frequency-flat channel, if it is configured to reflect the incident signal as a beam towards the receiver. However, the fundamental limitations of the IRS technology become apparent over practical frequency-selective channels, where the same configuration must be used over the entire bandwidth. In this paper, we consider a wideband orthogonal frequency-division multiplexing (OFDM) system that is supported by a fairly realistic IRS setup with two unbalanced states per element and also mutual coupling. We describe the simulation setup considered in the IEEE Signal Processing Cup 2021, propose a low-complexity solution for channel estimation and IRS configuration, and evaluate it on that setup.

中文翻译：

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为互耦下的 OFDM 通信优化二进制智能反射面

如果智能反射面 (IRS) 配置为将入射信号作为光束反射到接收器，则它可以大大提高频率平坦信道上的信道质量。然而，IRS 技术的基本限制在实际的频率选择信道上变得明显，其中必须在整个带宽上使用相同的配置。在本文中，我们考虑了一个宽带正交频分复用 (OFDM) 系统，该系统由一个相当现实的 IRS 设置支持，每个元素有两个不平衡状态以及相互耦合。我们描述了 2021 年 IEEE 信号处理杯中考虑的仿真设置，提出了一种用于信道估计和 IRS 配置的低复杂度解决方案，并在该设置上对其进行评估。