面向工业物联网中关键任务无线通信的低时延大规模天线技术

To meet the practical demand of ultra-reliable low-latency communications (URLLC) for wireless industrial Internet of things (IIoT), we propose an uplink multiuser massive multiple-input multiple-output (MIMO) design with non-coherent receivers, where the signal design for the multiuser joint space-time modulation and the corresponding error performance analysis are investigated. On the one hand, by fully taking advantage of the spatial diversity of the massive antenna array, the reliability of the overall system can be drastically improved in fading channels. On the other hand, by introducing non-coherent receivers at the physical layer, the delay caused by the estimation of instantaneous channel can be avoided; In the meanwhile, by developing a new unique factorization theory, the end nodes are allowed to transmit in a non-orthogonal multiple access (NOMA) scheme with finite-alphabet input signals, and hence the multiple access delay can be reduced. Only through the comprehensive design of these two aspects, we can meet the stringent requirements of industrial wireless on both high reliability and low latency. The main innovations lie in the application of the unique factorization theory of signals and the various asymptotic performance analyses and optimization for the considered non-coherent massive MIMO systems. This project will provide useful theoretical support for the steady development of industrial wireless and will also have a positive impact on the future implementation of Industry 4.0.

针对无线工业物联网对超高可靠、超低时延通信的实际需求，拟提出一种采用非相干接收机的多用户上行超大规模天线技术，研究其中多用户联合空时调制下的信号设计以及对应的错误性能分析。一方面，通过充分利用超大规模天线阵列的空间分集，提高系统面对衰落信道的可靠性。另一方面，在物理层通过非相干接收技术，避免估计瞬时信道带来的时延；在链路层通过发展一套完整的信号唯一分解理论，来解决采用有限字符输入信号的非正交多址接入问题，降低多接入时延。最终，通过这两个方面的综合设计，来同时满足工业无线对高可靠、低时延的性能要求。本项目的主要创新点在于信号唯一分解理论的运用和非相干超大规模天线系统的多种渐进性能分析与优化。本项目将为工业无线的持续发展提供有益的理论支持，并将对实现工业4.0的愿景产生积极的推动作用。

工业物联网(IIoT)对高灵活接入技术的实际需要推动了高可靠、低时延无线通信(URLLC)技术的快速发展。大规模多输入多输出(MIMO)系统被认为是实现URLLC的一种关键使能技术。然而，由于大规模MIMO的方案设计和性能在很大程度上取决于信道状态信息(CSI)的可用性，而大量CSI的估计必然导致额外的无线资源开销和延迟。针对这一问题，课题组主要研究了不需要CSI或导频序列的调制/解调传输方案，即基于能量调制和采用差分调制的方法。具体而言，主要进行了两种技术方案的研究：1)采用非相干能量调制/检测的低时延上行超大规模天线技术；2)采用非相干差分调制/检测的低时延上行超大规模天线技术。针对两种方案对应的发送信号联合设计、低复杂度接收机的实现方法、衰落信道下错误性能的分析与多用户联合发送功率优化等进行了深入研究，均取得显著的性能提升，为以后的实际无线通信系统提供了理论指导和技术保障。