ERI: SDR Beyond Radio: Enabling Experimental Research in Multi-Node Optical Wireless Networks via Software Defined Radio Tools and Techniques

无线通信生态系统仍然是现代社会中最具影响力的使能技术。由于我们的无线基础设施，我们有几乎无处不在的互联网接入。无线连接也允许更多的访问信息。无线物联网使远程控制各种设备成为可能——从咖啡壶到无人机或特斯拉。即使在没有人类用户的情况下，无线网络也可以通过机器对机器的通信将设备连接起来，并使我们不断增长的人工智能基础设施能够从远程传感器中获取大量数据。随着数据需求的不断增加，研究团体正在寻找支持未来无线的新技术。这包括对光无线通信（OWC）作为超密集无线网络的候选技术的重新兴趣。在高速海上交通运输方面取得了广泛进展；但是在考虑在密集环境中部署多用户和多小区OWC系统时，存在一些开放的挑战。该领域的大部分现有工作都是基于理论或模拟，只有很少的实验验证。这种趋势是由于工具包的可用性有限，这些工具包是开放访问的，并且具有对OWC波形的实时信号处理能力。考虑到过去二十年来射频通信的进步，射频社区显然受益于软件定义无线电（SDR）的概念和射频信号处理的相关工具。也就是说，SDR降低了进入门槛，使研究人员更有可能在物理上实例化新颖的想法，从而为无线通信研究创造了更公平的机会。本项目将通过开发一个与广泛使用的SDR软件和设备集成的开源OWC工具包，为OWC带来SDR的好处。该工具包将允许研究人员实施和分析多小区/多用户OWC网络的新技术。该工具包的工作流程从低级模拟扩展到实时实验分析，包括探索各种研究问题的机会，这些问题将使室内OWC网络的实际部署成为可能。开发的软件工具和硬件部署剧本将侧重于与密集OWC网络中的多址、小区间干扰和切换相关的测试系统。该项目还能够评估需要分布式发射器的光学无线系统，包括动态范围适应、空间调制和室内定位。最后，考虑了设备使用特性，以便更深入地了解密集网络中的设备运动/方向。由此产生的表征将最终提高模拟的准确性，旨在评估移动设备存在下的高度定向通信系统。该项目在基础的OWC研究和引入工具方面提供了优点，以使OWC社区能够在未来做出贡献。OWC系统的实验分析将提供与理论工作的基线比较，以验证理论/模拟模型或识别在此类系统建模中可能被忽视的独特特征。通过改进室内无线网络规模的动态设备模型，移动设备使用的特征也将为研究界提供价值。总之，该项目将为各种多单元/多用户OWC系统提供基线实验分析，并提供一个开源平台，允许其他OWC研究人员在实验系统中实现新颖的系统设计思想。通过这种方式，引入基于sdr的OWC工具将使以前专注于理论建模或仿真的OWC研究人员以及那些希望在OWC中开发研究项目的OWC研究人员更容易进行OWC系统的实验研究。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

The wireless communications ecosystem continues to be the most influential enabling technology in modern society. We have near-ubiquitous Internet access because of our wireless infrastructure. Wireless connectivity also allows for more than access to information. The wireless Internet of Things has enabled remote control over a breadth of devices – from a coffee pot to a drone or a Tesla. Even in the absence of a human user, wireless networks connect devices in machine-to-machine communications, and they allow our ever-growing artificial intelligence infrastructure to consume massive amounts of data from remote sensors. As data demand continues to increase, the research community is looking towards novel technologies to support the future of wireless. This includes a renewed interest in optical wireless communication (OWC) as a candidate technology for ultra-dense wireless networks. There has been extensive progress in highspeed OWC links; but there are open challenges when considering deployment of multi-user and multi-cell OWC systems in dense environments. Much of the existing work in this area is based in theory or simulation with minimal experimental validation. This tendency is due to the limited availability of toolkits that are openly accessible and possess real-time signal processing capabilities for OWC waveforms. Considering the advancements in RF communications over the past two decades, the RF community has clearly benefited from the concept of software defined radio (SDR) and related tools for RF signal processing. Namely, SDR has created a more equitable opportunity for research in wireless communications by reducing the barrier to entry and making it more feasible for researchers to physically instantiate novel ideas. This project will bring the benefits of SDR to OWC through development of an open-source OWC toolkit that integrates with widely used SDR software and equipment. The toolkit will allow researchers to implement and analyze novel techniques for multi-cell/multi-user OWC networks.The toolkit’s workflow scales from low-level simulation to real-time experimental analysis, including opportunities to explore a variety of research problems that would enable practical deployment of indoor OWC networks. The developed software tools and hardware deployment playbooks will focus on test systems related to multiple access, intercell interference, and handover in dense OWC networks. This project also enables evaluation of optical wireless systems that require distributed transmitters – including dynamic range adaptation, spatial modulation, and indoor positioning. Lastly, device usage characterization is considered in order to provide a deeper understanding of device motion/orientation in dense networks. The resulting characterization will ultimately improve the accuracy of simulations that aim to evaluate highly directional communication systems in the presence of mobile devices. The project offers merit in fundamental OWC research and in the introduction of tools to enable future contributions from the OWC community. The experimental analysis of OWC systems will provide a baseline comparison with theoretical work to either validate theoretical/simulated models or recognize the unique characteristics that may have been overlooked in modeling such systems. Characterization of mobile device usage will also offer value to the research community by improving models for dynamic devices at the scale of indoor wireless networks. In summary, this project will provide baseline experimental analysis for a variety of multi-cell/multi-user OWC systems along with an open-source platform that allows other OWC researchers to bring novel system design ideas to fruition in experimental systems. In this way, the introduction of SDR-based OWC tools will make experimental research in OWC systems more accessible to OWC researchers who have previously focused on theoretical modeling or simulation, and to those who are looking to develop a research program in OWC.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.