SCISRS: Signal Cancellation using Intelligent Surfaces for Radio Astronomy Services
SCISRS: Signal Cancellation using Intelligent Surfaces for Radio Astronomy Services
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DOI：
10.1109/globecom48099.2022.10001662
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发表时间：
2022-12
期刊：
影响因子：
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通讯作者：
Zhibin Zou;Xue Wei;D. Saha;Aveek Dutta;G. Hellbourg
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文献类型：
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作者：
Zhibin Zou;Xue Wei;D. Saha;Aveek Dutta;G. Hellbourg
最近，人们对促进电磁(EM)频谱的主动和被动用户共存产生了极大的兴趣，主要目标是提高频谱利用率。射电天文学服务(RAS)等被动用户面临的主要挑战是，需要极其安静的天空才能以射电望远镜的最高灵敏度进行天文观测。由于分配的频谱越来越密集，无处不在的无线通信呈指数增长，以及观测快速射电爆发所需的带外天文观测，这一点越来越难以保证。这需要主动和被动用户之间的双向合作，或者在望远镜现场进行创新的信号处理，以消除任何入射的无线电频率干扰(RFI)。在这项工作中，我们展示了这种范例的可行性，其中来自机载源(例如飞机、LEO卫星等)的RFI在射电望远镜的接收器处被消除，方法是通过可重构智能表面(RIS)阵列来整形EM波前。与RIS传统的波束归零应用不同，这种方法需要RIS精确计算反射信号的相位和幅度，以确保完全消除入射RFI。我们在实际环境中对这种方法进行了仿真，研究了它的误差性能和系统参数的边界条件，这将在不久的将来产生一个可演示的原型。结果表明，在海拔60美元、高度10000 m的ADS-B系统中，一个包含364个阵元的RIS阵列可以完全抵消射频干扰。
Recently, there has been great interest in facilitating coexistence of active and passive users of the electromagnetic (EM) spectrum, with the primary objective of higher spectral utilization. The major challenge for passive users, such as Radio Astronomy Services (RAS), is the need for extremely quiet skies to make astronomical observations with maximum sensitivity of the radio telescope. This is increasingly difficult to guarantee because of densification of allocated spectrum, exponential growth of ubiquitous wireless communication and out-of-band astronomical observations required to observe fast radio bursts. This requires either bidirectional collaboration between active and passive users or innovative signal processing at the telescope site to cancel any incident Radio Frequency Interference (RFI). In this work, we show the feasibility of such a paradigm, where RFI from airborne sources, e.g., aircraft, LEO satellites, etc., is cancelled at the receiver of a Radio Telescope, by shaping the EM wavefront by an array of Reconfigurable Intelligent Surfaces (RIS). In contrast to conventional beam-nulling applications for RIS, this method requires precise calculation of the phase and the amplitude of the reflected signal by the RIS in order to guarantee complete cancellation of the incident RFI. We simulate this approach in a practical setting to study its error performance and boundary conditions of the system parameters, that will lead to a demonstrable prototype in near future. Our results indicate that an RIS array with 364 elements can fully cancel RFI for ADS-B systems at an elevation of $60^{\circ}$ and an altitude of 10000 m.