6G信道新特性与建模研究:挑战、进展与展望

Channel characteristics and modeling research for 6G:challenges,progress,and prospects

随着第六代移动通信(the six generation,6G)的前沿研究在全球范围内陆续开展,工业界和学术界提出了多种新技术、新频段和新应用,如通信感知一体化(integrated sensing and communication,ISAC)、超大规模多输入多输出天线阵列(extra-large-scale massive multiple-input multiple-output,XLMIMO)、多频段通信、可重构智能超表面(reconfigurable intelligent surface,RIS)和空-天-地-海通信等,旨在提供更高速率、更低时延、更广覆盖的高可靠移动通信服务.信道是移动通信系统收发端之间信号承载的媒介,其深入的传播特性发现与精确的建模对6G系统的研发、评估和优化至关重要.因此本文首先回顾了第一代到第五代移动通信的信道研究发展趋势,指出了多频段、多场景和多种新技术趋势下6G信道研究面临的挑战.随后,详细总结了6G信道新特性研究的最新进展,包括ISAC信道的共享性、XL-MIMO信道的近场和空间非平稳性、RIS信道的级联特性,以及多频段信道频率依赖性等.然后,本文提出了一种面向6G标准的扩展几何统计性信道模型,将所发现的信道新特性纳入统一建模框架,所提模型后向兼容主流的高精度5G标准模型,便于代际更迭的信道仿真器实现.最后,指出了面向6G演进的信道特性与建模方法研究有待深入的问题,并聚焦6G网络自治化的未来愿景,展望了一种基于环境感知重构和人工智能预测技术的信道数字孪生新范式.

As research on the sixth generation(6G)of mobile communication launches globally,various new technologies,frequency bands,and applications have been proposed by researchers from both industry and academia.These include integrated sensing and communication(ISAC),extra-large-scale massive multiple-input multiple-output(XL-MIMO),multi-band communication,recon gurable intelligent surface(RIS),and space-air-ground-sea,aimed at providing mobile communication services with higher data rates,lower latency,and broader coverage.Channels serve as the medium for signal transmission between transmitters and receivers in mobile communication systems,and a profound understanding of their propagation characteristics and precise modeling are crucial for the development,evaluation,and optimization of 6G system.Hence,this paper begins with a review of the developmental trends in channel research from the rst to the fth generation of mobile communication,highlighting the challenges faced by 6G channel research under the trends of multi-bands,multi-scenarios,and various new technologies.Subsequently,this paper provides a comprehensive summary of the latest progress in the research of new characteristics of 6G channels,including the sharing feature of ISAC channels,the near-eld and spatial non-stationarity of XL-MIMO,frequency dependency across multiple channel bands,and the cascading nature of RIS channels.Then,an extension of geometry-based stochastic channel models tailored for 6G standards is proposed,integrating the discovered channel characteristics into a uni ed modeling framework.The proposed model is backward-compatible with mainstream high-precision 5G standards models,facilitating the realization of intergenerational channel simulators.Finally,it identi es open issues in the research on channel characteristics and modeling methods for 6G evolution,focusing on the future vision of 6G network autonomy and envisioning a new paradigm of channel digital twin based on environmental perception reconstruction and arti cial intelligence prediction technologies.