CIF: Small: Fundamental Communication Latency Limits Beyond the Traditional Block-Coding Architecture

先进的无线通信网络推动了许多技术的进步，从智能手机的便利性、个性化的健康监测设备，到用于精准农业的智能土壤/作物传感器，仅举几例。虽然在过去几十年里，通过无线网络传输的数据量通过信号处理的众多创新呈指数级增长，但在减少无线通信的延迟(即响应时间)方面的进展却明显较少。该项目旨在通过首先描述被称为块编码体系结构的普遍使用的设计范例的缺陷来显著缩短无线通信延迟。然后，该项目将设计基于非块编码的解决方案，显著降低延迟，超出标准块编码体系结构的可能。无线通信新的超快响应时间将支持物联网、边缘计算和网络物理系统中复杂、多样和高度动态的应用，并可能释放出无数新的变革性应用，超出当今技术的想象。在对超低延迟的不懈追求中，系统设计者必须利用每一种减少延迟的来源，因此本项目采取多管齐下的方法，同时最小化网络级的解码和放大转发延迟、链路级的排队延迟和信号级的同步延迟。在网络层面，该项目将通过设计一种基于孤子的级联机制来重塑放大-放大-转发方案，该机制利用放大-放大-转发的超低延迟，而不存在其主要缺点--误差累积。对于链路级别，将开发新的基于随机游走的分析和设计工具，作为新的无阻塞设计的理论基础，这些设计通过连续的动态分组编码完全消除排队延迟。对于信号级，本项目提出了一种在最快变化检测框架下的无速率设计。由此产生的方案将显著改善链路启动/同步时间，这是向物联网设备发送短而零星的消息时延迟的主要来源。该项目的理论成果应该会导致新的实用设计，获得超过任何基于块的解决方案的超低延迟优势，并在其他重要学科中开辟新想法，包括在嘈杂的社交网络上可靠和快速的信息传播，以及在不可靠的通信网络上的分布式计算。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。

Advanced wireless communication networks have driven many technological advances ranging from the convenience of smartphones, personalized health monitoring devices, to smart soil / crop sensors for precision agriculture, to name but a few. While the amount of data that can be delivered through wireless networks has increased exponentially in the past decades through numerous innovations of signal processing, there has been significantly less progress on the reduction of latency (i.e., response time) of wireless communications. This project aims to substantially shorten the wireless communication latency by first characterizing the drawbacks of the ubiquitously used design paradigm called the block coding architecture. The project will then design non-block-coding-based solutions that significantly lower the latency beyond what is considered possible under standard block-coding architectures. The new ultra-fast response time of wireless communications will support complex, diverse, and highly dynamic applications in Internet-of-Things, edge computing, and cyber-physical systems, and may yet unlock countless new transformative applications beyond what is conceivable under today's technologies. In the relentless pursuit of ultra-low latency, a system designer must utilize every source of delay reduction, and this project thus takes a multi-pronged approach that minimizes, simultaneously, the decode-&-forward delay in the network level, the queueing delay in the link level, and the synchronization delay in the signal level. For the network level, the project will reinvent amplify-&-forward schemes by designing a soliton-based concatenation mechanism that takes advantage of the ultra-low latency of amplify-&-forward without its main drawback of error accumulation. For the link level, new random-walk-based analysis and design tools will be developed as the theoretical foundation for new blockless designs that eliminate queueing delay completely through continuous, on-the-fly packet encoding. For the signal level, this project proposes a rateless design under the framework of quickest change detection. The resulting scheme would significantly improve the link start-up / synchronization time, a major source of delay when sending short, sporadic messages to Internet-of-Things devices. The theoretical results of this project should lead to new practical designs that harvest the ultra-low latency benefits beyond any block-based solutions and open up new ideas in other important disciplines, including reliable and fast information propagation over noisy social networks, and distributed computation over unreliable communication networks.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.