[论文解读] White Paper on Broadband Connectivity in 6G

Nandana Rajatheva, Italo Atzeni+23 more|arXiv (Cornell University)|Apr 29, 2020

Advanced Wireless Communication Technologies参考文献 95被引用 291

一句话总结

本白皮书概述了通往宽带级别的6G连接的路径，详细阐述实现 Tbps 级峰值速率和超高可靠低时延通信所需的基础设施、频谱和协议使能因素，包括与空间网络和全息无线概念的整合。

ABSTRACT

This white paper explores the road to implementing broadband connectivity in future 6G wireless systems. Different categories of use cases are considered, from extreme capacity with peak data rates up to 1 Tbps, to raising the typical data rates by orders-of-magnitude, to support broadband connectivity at railway speeds up to 1000 km/h. To achieve these goals, not only the terrestrial networks will be evolved but they will also be integrated with satellite networks, all facilitating autonomous systems and various interconnected structures. We believe that several categories of enablers at the infrastructure, spectrum, and protocol/ algorithmic levels are required to realize the intended broadband connectivity goals in 6G. At the infrastructure level, we consider ultra-massive MIMO technology (possibly implemented using holographic radio), intelligent reflecting surfaces, user-centric and scalable cell-free networking, integrated access and backhaul, and integrated space and terrestrial networks. At the spectrum level, the network must seamlessly utilize sub-6 GHz bands for coverage and spatial multiplexing of many devices, while higher bands will be used for pushing the peak rates of point-to-point links. The latter path will lead to THz communications complemented by visible light communications in specific scenarios. At the protocol/algorithmic level, the enablers include improved coding, modulation, and waveforms to achieve lower latencies, higher reliability, and reduced complexity. Different options will be needed to optimally support different use cases. The resource efficiency can be further improved by using various combinations of full-duplex radios, interference management based on rate-splitting, machine-learning-based optimization, coded caching, and broadcasting.

研究动机与目标

• 将 6G 宽带连接用例定位为下一代无线系统的核心驱动，以激发发展。
• 识别实现 Tbps 峰值速率与全球覆盖所需的基础设施、频谱和协议/算法使能因素。
• 提出一种多层方法，结合超大规模 MIMO、智能反射面、综合的空间-地面网络，以及先进的编码/波形。
• 突出跨 sub-6 GHz 到 THz 与可见光波段的 KPI 目标和频谱策略。

提出的方法

• 对 6G 宽带使能因素在三个层次上的提案进行综述：基础设施、频谱，以及协议/算法的发展。
• 对用例和 KPI 的分析，推动 Tbps 规模宽带连接的设计选择。
• 将全息无线描述为实现连续孔径大规模 MIMO 与高维空间多路复用的路径。
• 评估 IRS 与集成网络在高频段提升传播和覆盖的效果。

实验结果

研究问题

• RQ1 实现 6G 宽带连接所需在基础设施、频谱和协议层面的使能技术有哪些？
• RQ2 6G 如何在实现 Tbps 峰值速率的同时，确保超低时延、极高可靠性和广域覆盖？
• RQ3 超大规模MIMO、全息无线与智能反射面在 6G 性能提升中扮演什么角色？
• RQ4 空间-地面一体化与边缘计算如何支持在多样化环境中的 6G 宽带用例？
• RQ5 跨 sub-6 GHz 到 THz 及可见光波段的何种频谱策略最有利于实现 6G 宽带目标？

主要发现

• 6G 宽带目标峰值速率高达 1 Tbps，用户体验速率约 1 Gbps，某些用例下时延降至 0.1 ms。
• 需要多层使能方针，结合基础设施（ultra-maste MIMO、全息无线、IRS、综合接入/回程、空间-地面网络）、频谱（sub-6 到 THz 与 VLC）以及协议/算法进展（编码、调制、波形、双工、基于 ML 的优化）。
• 超密集、协同网络（无小区）和集成的空间/地面系统是实现全覆盖的核心。
• 全息无线和连续孔径有源天线使得空间多路复用远高于波束空间方法，尤其在高频段。
• 智能反射面提供被动波束成形增益，以缓解高频段传播挑战并支持网络优化。
• ML 辅助优化、编码缓存和速率分割是实现效率与适应性的重要协议级工具。