Wireless networks-on-chip (WNoCs) are an enticing complementary interconnect technology for multi-core chips but face severe resource constraints. Being limited to simple on-off-keying modulation, the reverberant nature of the chip enclosure imposes limits on allowed modulation speeds in sight of inter-symbol interference, casting doubts on the competitiveness of WNoCs as interconnect technology. Fortunately, this vexing problem was recently overcome by parametrizing the on-chip radio environment with a reconfigurable intelligent surface (RIS). By suitably configuring the RIS, selected channel impulse responses (CIRs) can be tuned to be (almost) pulse-like despite rich scattering thanks to judiciously tailored multi-bounce path interferences. However, the exploration of this “over-the-air” (OTA) equalization is thwarted by (i) the overwhelming complexity of the propagation environment, and (ii) the non-linear dependence of the CIR on the RIS configuration, requiring a costly and lengthy full-wave simulation for every optimization step. Here, we show that a reduced-basis physics-compliant model for RIS-parametrized WNoCs can be calibrated with a single full-wave simulation. Thereby, we unlock the possibility of predicting the CIR for any RIS configuration almost instantaneously without any additional full-wave simulation. We leverage this new tool to systematically explore OTA equalization in RIS-parametrized WNoCs regarding the optimal choice of delay time for the RIS-shaped CIR’s peak. We also study the simultaneous optimization of multiple on-chip wireless links for broadcasting and conduct a performance evaluation in terms of the bit error rate. Looking forward, the introduced tools will enable the efficient exploration of various types of OTA analog computing in RIS-parametrized WNoCs.

中文翻译：

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RIS 参数化无线片上网络中空中信道均衡的系统物理兼容分析


无线片上网络（WNoC）对于多核芯片来说是一种极具吸引力的互补互连技术，但面临着严重的资源限制。由于仅限于简单的开关键控调制，芯片外壳的混响特性在符号间干扰的情况下对允许的调制速度施加了限制，使人们对 WNoC 作为互连技术的竞争力产生怀疑。幸运的是，这个棘手的问题最近通过使用可重构智能表面（RIS）对片上无线电环境进行参数化得到了解决。通过适当配置 RIS，选定的通道脉冲响应 (CIR) 可以调整为（几乎）类脉冲，尽管由于明智定制的多次反射路径干扰而产生丰富的散射。然而，对这种“空中”(OTA) 均衡的探索受到以下因素的阻碍：(i) 传播环境极其复杂，(ii) CIR 对 RIS 配置的非线性依赖性，需要每个优化步骤都需要昂贵且漫长的全波模拟。在这里，我们展示了 RIS 参数化 WNoC 的减基物理兼容模型可以通过单个全波仿真进行校准。因此，我们几乎可以立即预测任何 RIS 配置的 CIR，而无需任何额外的全波仿真。我们利用这个新工具系统地探索 RIS 参数化 WNoC 中的 OTA 均衡，了解 RIS 形 CIR 峰值延迟时间的最佳选择。我们还研究了用于广播的多个片上无线链路的同时优化，并根据误码率进行了性能评估。 展望未来，引入的工具将能够在 RIS 参数化 WNoC 中有效探索各种类型的 OTA 模拟计算。