SpecEES: Collaborative Research: Efficient and Secure Access to Spectrum up to THz

自马可尼时代以来，批评者就抱怨无线传输缺乏安全性，而且速度太慢，以至于像拜伦勋爵在1898年著名的打趣那样，骑在小马上的男孩会更快地传递信息。一个多世纪后，太赫兹(THz)规模的每秒太比特链路指日可待，而高度定向的光束已经被设计成安全的。然而，如果在为移动客户端反复重新对准波束时遭遇中断，即使是太赫兹链路也可能变得“太慢”。同样，虽然60千兆赫(GHz)频段因其更高的安全性而备受赞誉，但不幸的是，即使是笔束太赫兹规模的链路也可能容易受到敏捷窃听的攻击。因此，该项目的目标是设计、实施和实验探索概念验证系统，以实现无线局域网(WLAN)架构，该架构具有从100 GHz到1 THz的高效、安全的频谱接入，以及最大120米的无线局域网范围。该项目将建立在太赫兹规模的设备和频谱实现的基本新传输能力的基础上。第一个项目推力将实现Leaky X-Agon，这是同类产品中第一个多面泄漏波导WLAN架构。该架构将频率和转向角度结合在一起，以提供频率选择性自适应波束转向，从而实现前所未有的链路空间密度。此外，通过在每个面上传输宽带“太赫兹彩虹”，实现了波束转向和频率选择的新基础：通过在不同角度发射不同频率，接收器可以同时识别所有传播路径及其转向角度，而不是目前普遍采用的耗时和低效的反复试验。第二个项目旨在解决安全问题，并为确保从100 GHz到1 THz的频谱接入提供实验分析和对策。在强对手威胁模型下，该项目推力将开发使用太赫兹后向散射和太赫兹彩虹失真的方法来检测和避开窃听者可能用来帮助拦截传输的对象。此外，还提出了一种新的吸收调谐方法来调整传输距离，使得超出预期接收器位置的拦截是不可行的。利用精确的经验模型，该方法将把载波频率调整到接近水蒸气吸收共振的频率，从而精确地控制大气传播损耗，从而控制传输范围。所有项目组成部分都以空中实验和验证的广泛实施和实验计划为特色。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Since the days of Marconi, critics complained that wireless transmission lacked security and was so slow that a boy on a pony would be a faster way to transmit a message, as Lord Byron famously quipped in 1898. Over a century later, terabit-per-second links in terahertz (THz) scale spectrum are around the corner and highly directional beams have been decreed secure by design. However, even THz links can become "too slow" if they suffer from outages while repeatedly re-aligning beams for mobile clients. Likewise, while 60 gigahertz (GHz) bands have been lauded for their improved security, unfortunately, even pencil-beam THz-scale links can be vulnerable to agile eavesdroppers. Consequently, this project targets to design, implement, and experimentally explore proof-of-concept systems to realize a Wireless Local Area Network (WLAN) architecture with efficient and secure access to spectrum from 100 GHz up to 1 THz and WLAN-scale range up to 120 meters. This project will build on fundamental new transmission capabilities enabled by THz-scale devices and spectrum. The first project thrust will realize Leaky X-Agon, a first-of-its-kind multi-face leaky waveguide WLAN architecture. This architecture couples frequency and steering angle to provide frequency-selective adaptive beam steering enabling unprecedented spatial density of links. Moreover, a new foundation for beam steering and frequency selection is realized via transmission of a wideband "THz rainbow" on each face: by emitting different frequencies at different angles, the receiver can identify all propagation paths and their steering angles simultaneously, as opposed to time-consuming and inefficient trial-and-error testing that is commonly employed today. The second project thrust addresses security and provides experimental analysis and counter-measures for securing spectrum access from 100 GHz to 1 THz. Under a strong adversary threat model, this project thrust will develop methods using THz backscatter and THz rainbow distortion to detect and avoid objects that an eavesdropper may be using to aid interception of a transmission. Moreover, a novel absorption tuning method is proposed to tune the transmission range so that interception beyond the location of the intended receiver is not viable. Using accurate empirical models, the method will tune the carrier frequency to be close to that of a water vapor absorption resonance, yielding exquisite control of the atmospheric propagation loss, and therefore of the transmission range. All project components feature an extensive implementation and experimental plan for over-the-air experiments and validation.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.