[论文解读] Over-the-Air Computation for 6G: Foundations, Technologies, and Applications

Zhibin Wang, Yapeng Zhao+4 more|arXiv (Cornell University)|Oct 19, 2022

Data Management and Algorithms参考文献 192被引用 23

一句话总结

对空中计算（AirComp）的全面综述，详细介绍其基础、架构、设计技巧、实现挑战，以及在物联网和边缘智能中对6G的应用。

ABSTRACT

The rapid advancement of artificial intelligence technologies has given rise to diversified intelligent services, which place unprecedented demands on massive connectivity and gigantic data aggregation. However, the scarce radio resources and stringent latency requirement make it challenging to meet these demands. To tackle these challenges, over-the-air computation (AirComp) emerges as a potential technology. Specifically, AirComp seamlessly integrates the communication and computation procedures through the superposition property of multiple-access channels, which yields a revolutionary multiple-access paradigm shift from "compute-after-communicate" to "compute-when-communicate". By this means, AirComp enables spectral-efficient and low-latency wireless data aggregation by allowing multiple devices to occupy the same channel for transmission. In this paper, we aim to present the recent advancement of AirComp in terms of foundations, technologies, and applications. The mathematical form and communication design are introduced as the foundations of AirComp, and the critical issues of AirComp over different network architectures are then discussed along with the review of existing literature. The technologies employed for the analysis and optimization on AirComp are reviewed from the information theory and signal processing perspectives. Moreover, we present the existing studies that tackle the practical implementation issues in AirComp systems, and elaborate the applications of AirComp in Internet of Things and edge intelligent networks. Finally, potential research directions are highlighted to motivate the future development of AirComp.

研究动机与目标

• 总结 AirComp 的数学基础与通信设计。
• 评述 AirComp 在单小区、蜂窝间、多小区、分层、RIS 辅助、无人机辅助及其他网络中的应用。
• 讨论信息理论与信号处理方法在 AirComp 设计与优化中的应用。
• 指出物联网和边缘智能中的实际实现问题与现实世界应用。
• 突出 AirComp 的开放挑战与未来研究方向。

提出的方法

• 将名义函数表示作为 AirComp 的核心数学基础。
• 将 AirComp 表述为利用 MAC 波形叠加的“计算在通信时”范式。
• 区分编码 AirComp 与非编码 AirComp，并给出它们的权衡（速率与失真）。
• 将计算速率和计算精度定义为主要性能指标。
• 调研网络架构与同步情况，并总结设计策略（功率控制、波束赋形、IA/SIA、中继）。
• 讨论实际问题及应用以促使未来工作。

实验结果

研究问题

• RQ1 AirComp 的数学形式是什么？哪些函数可以通过 AirComp 计算？
• RQ2 AirComp 如何在不同网络架构下实现（单小区、蜂窝、多小区、分层、RIS/UAV）？
• RQ3 AirComp 的关键设计技术与性能指标是什么（编码与模拟、同步、干扰管理）？
• RQ4 在为物联网和边缘智能网络实现 AirComp 时，会出现哪些实际挑战，以及未来的研究方向？

主要发现

• AirComp 通过利用波形叠加来聚合数据以实现对名义函数的计算，从而实现“计算在通信时”。
• 主要有两种 AirComp 范式：编码 AirComp（使用结构化码）和无编码 AirComp（模拟，进行幅度/相位对齐）。
• 计算速率与计算精度被确立为核心指标，区别于传统的可靠传输速率和失真。
• AirComp 已在多种架构下研究（单小区、蜂窝、多小区、RIS 辅助、UAV 辅助），采用多种干扰管理与同步技术。
• 实际实现解决同步、与传统服务共存，以及基于中继的分层网络以扩展到大规模部署。