异质无蜂窝MIMO绿色通信网络

Heterogeneous Cell-Free MIMO Green Communication Network

异质无蜂窝多天线(Multiple-Input Multiple-Output,MIMO)系统是未来移动网络发展的方向之一,也是极具节能潜力的高效通信系统。本文首先对异质无蜂窝MIMO系统的整体构架进行了介绍,从整体的角度分析该网络的具体构架和节能潜力,随后从绿色网络部署与协作、网络运行与调度以及用户接入、高能效MIMO收发机技术和传输与多址等方面介绍了基本原理和潜在节能增益。随着信息超材料的发展,一些全新的异质MIMO收发机逐渐展现了其在能效方面的优势,合理利用这些新型的收发机技术将有效提高系统能效。除了硬件带来的增益之外,异质无蜂窝组网的增益主要来源于各个接入点的协作传输所形成的超大规模MIMO,而这也带来了更加复杂的信号传输模式,同时受限于有限的算力资源,系统不可能无限协作,因此需要对该系统的接入点部署策略和协作方式进行全新的研究。在完成部署之后,由于用户在空间和时间上的通信需求变化较大,还可以利用深度学习等技术对用户的行为进行一定程度的预测,并在空间和时间上对通信设备的运行状态进行调整,在满足通信指标的同时提高系统的能效。最后,用户的多址接入与传输方式则是整个异质无蜂窝MIMO系统的基础,新型的速率分割多址接入(Rate-Splitting Multiple Access,RSMA)技术可以有效对抗干扰,而针对异质无蜂窝MIMO系统的传输波束赋形也需要进行全新的设计以适应RSMA技术和异质的MIMO设备。本文还同时讨论了以上各个方面的可能设计以及未来研究方向。

A heterogeneous cell-free multiple-input multiple-output(MIMO)system is one of the development directions of future mobile networks,as it is an efficient communication system with great energy saving potential.This paper first introduces the overall architecture of heterogeneous cell-free MIMO systems;then analyzes the specific architecture and energy saving potential of the network from a holistic perspective;and introduces the basic principles and potential energy saving gains from green network deployment and collaboration,network operation and scheduling,user access,energy-efficient MIMO transceiver technology,and transmission and multiple access.With the development of information metamaterials,several novel heterogeneous MIMO transceivers have gradually shown their advantages in energy efficiency.Rational use of these new transceiver technologies will effectively improve the energy efficiency of the system.In addition to the gain brought by the hardware,the gain of heterogeneous cell-free networking mainly comes from the massive MIMO formed by the cooperative transmission of various access points,which also brings more complex signal transmission modes.Simultaneously,limited by computing resources,the system cannot cooperate in an unlimited manner;thus,research must be conducted on the deployment strategy and cooperation mode of the access point of the system.After deployment,in response to large changes in the user’s communication needs in space and time,deep learning and other technologies can be used to predict the user’s behavior to a certain extent,and adjust the operating state of the communication equipment in space and time,to meet the communication indicators and improve the energy efficiency of the system.Finally,the user’s multiple access and transmission mode is the basis of the entire heterogeneous cell-free MIMO system,and the new rate-splitting multiple access(RSMA)technology can effectively combat interference.Transmission beamforming for heterogeneous cell-free MIMO systems also requires a new design to adapt to RSMA technology and heterogeneous MIMO devices.This paper also discusses the possible design and future research direction of the abovementioned aspects.