Title: Delay-Augmented Stacked Intelligent Surfaces: Potential, Challenges, and Opportunities Show Chinese title

Title: 延迟增强的堆叠智能表面：潜力、挑战与机遇

Abstract: Stacked intelligent surfaces (SIS)s have been proposed recently as an enabling technology for Holographic Multiple Input Multiple Output (HMIMO) and Ultra-massive MIMO (umMIMO) technologies. Their utility can extend beyond spatial wave-domain processing of signals if they are enhanced with strategically-tuned symbol-duration level delays to enable temporal processing as well. In this work, we introduce the idea of a delay-augmented SIS (DA-SIS). We shed light on the feasibility of realizing delay units in an SIS. Then, we discuss the relevance of the proposed DA-SIS and present a use case that illustrates its potential, wherein the DA-SIS serves as an analog equalizer that aids in eliminating multi-path-induced inter-symbol-interference (ISI). We show how the number of elements affect the equalization process using the bit error rate (BER) as a metric, and demonstrate the potential of the DA-SIS in equalization via comparing with digital equalizers as a benchmark. Finally, we present opportunities and future research directions that can be undertaken to bring this idea to fruition. Show Chinese abstract

Abstract: 堆叠智能表面（SIS）最近被提出作为全息多输入多输出（HMIMO）和超大规模多输入多输出（umMIMO）技术的使能技术。 如果在SIS中引入经过精心调整的符号持续时间级别的延迟，它们的用途可以超越信号的空间波域处理，从而实现时间处理。 在本工作中，我们引入了延迟增强型SIS（DA-SIS）的概念。 我们探讨了在SIS中实现延迟单元的可行性。 然后，我们讨论了所提出的DA-SIS的相关性，并提供了一个使用案例，说明其潜力，其中DA-SIS作为模拟均衡器，有助于消除多路径引起的符号间干扰（ISI）。 我们使用误码率（BER）作为度量标准，展示了元件数量如何影响均衡过程，并通过与数字均衡器进行比较，展示了DA-SIS在均衡方面的潜力。 最后，我们提出了可以开展的研究机会和未来研究方向，以实现这一理念。