面向超大规模MIMO的混合远近场通信

Mixed Near-and Far-field Communications forExtremely Large-scale MIMO

超大规模多输入多输出(Extremely Large-scale Multiple-Input Multiple-Output, XL-MIMO)是未来6G通信系统的一个关键备选技术,可以大幅度提升未来通信系统的性能,如超高的频谱效率和空间分辨率、超低时延等。不同于现有研究工作主要关注于近场通信或远场通信,考虑更加实际的混合远近场通信场景,即通信系统中同时存在近场和远场用户。介绍了XL-MIMO系统中考虑混合远近场通信范式的重要性和混合远近场通信的信道建模,指出混合远近场通信场景中固有的关键特征,即能量扩散效应;详细介绍了3种典型的混合远近场通信场景:混合远近场的干扰分析、无线信能同传、物理层安全。针对上述典型场景,指出其在混合远近场通信中相较于近场通信/远场通信的根本区别和面临的关键设计难题。总结了混合远近场通信中仍需关注和亟待解决的开放性问题。

Extremely Large-scale Multiple-Input Multiple-Output(XL-MIMO)is a key candidate technology for future 6G communication systems,which can significantly improve the performance of future communication systems,featuring ultra-high spectral efficiency and spatial resolution,ultra-low latency,etc.In contrast to existing works that mostly focus on either near-field communications or far-field communications,a novel yet practical communication scenario is considered,namely mixed near-and far-field communications,in which there exist both near-and far-field users.Specifically,the importance of considering the mixed near-and far-field communication paradigm in XL-MIMO systems is first introduced,followed by a brief introduction to the channel modeling for mixed-field communications,and a key feature inherent in mixed-field communications,namely the energy-spread effect.Next,three typical mixed-field communication scenarios are introduced in detail,namely,mixed-field interference analysis,simultaneous wireless information and power transfer,and physical layer security.For above typical scenarios,fundamental differences and key design issues encountered in mixed-field communication systems as compared with near-/far-field communication systems are elaborated.Finally,open issues that deserve future investigation in mixed-field communications are summarized.