Intelligent Reflecting Surface Empowered Transmission Techniques for Next-Generation Communication Systems

下一代通信系统有望支持爆炸性的数据速率和超低延迟传输，并实现无处不在的连接。这种严格的要求对现有的蜂窝系统基础设施提出了严峻的挑战，探索能够实现更高频谱和能量效率的新颖和创新的传输技术来满足这些需求是非常有意义的。在过去的几十年里，已经提出了各种先进的技术来促进在收发信机处的信号发送和接收，然而，对无线传播环境的关注很少。事实上，无线传播环境长期以来一直被认为是收发信机之间不可控和随机行为的实体。除了无法控制外，由于信号衰减、衰落和引入干扰，环境通常对通信效率产生不利影响。近年来，对能够利用传播环境的随机性以提高通信效率或简化收发机体系结构的新的通信范例的需求不断增加。在这方面，智能反射面(IRS)由于能够通过软件控制反射来重新配置传播环境而受到极大的关注。红外反射器是由许多低成本的被动反射元件组成的平面，每个元件都能够引起入射信号的幅度和相位变化，以实现细粒度的反射波束形成。这项建议将研究新的IRS授权的传输技术，以实现我们的长期目标，即通过以下三个短期努力提高下一代蜂窝系统的频谱和能量效率：1)为IRS辅助系统开发新颖且低复杂度的资源分配和波束形成技术；2)研究IRS与下一代通信系统的其他候选技术的集成，如毫米波、非正交多址和物理层安全；3)分析和量化各种传输损伤，如不完善的信道状态信息、离散相移和随机相位噪声对IRS辅助传输性能的影响，并开发新的信号处理技术来对抗这些损伤。拟议的研究计划将提供一个系统框架，以解决IRS授权的物理层传输中的各种设计问题，并进一步提高下一代蜂窝系统的性能。因此，这些研究成果有望引起学术界和产业界的关注，并导致研究合作。同时，拟议的研究计划将培训和装备高素质的通信理论和信号处理方面的基本技能，为加拿大的技术和学术部门做出贡献。

Next-generation communication systems are expected to support explosive data rate and ultra-low latency transmissions and enable pervasive connectivity. Such stringent requirements pose serious challenges on the existing cellular systems infrastructure, and it is of great interest to explore novel and innovative transmission techniques that can achieve higher spectral- and energy-efficiencies to meet such demands. Over the past decades, various advanced techniques that facilitate signal transmission and reception at the transceivers have been proposed, however little attention has been paid to the wireless propagation environment. Indeed, the wireless propagation environment has long been perceived as an uncontrollable and randomly behaving entity between the transceivers. Aside from being uncontrollable, the environment usually has an adverse impact on the communication efficiency, owing to the signal attenuation, fading and interference introduced. Recently, there is increasing demand for novel communication paradigms that can exploit the randomness of the propagation environment, either to increase the communication efficiency or to simplify the transceiver architecture. In this regard, intelligent reflecting surface (IRS) has received great attention owing to its ability to reconfigure the propagation environment via software-controlled reflection. An IRS is a planar surface consisting of many low-cost passive reflecting elements, each able to induce an amplitude and phase change to the incident signal to achieve fine-grained reflective beamforming. This proposal will investigate novel IRS-empowered transmission techniques to realize our long-term goal of increasing the spectral- and energy-efficiencies of next-generation cellular systems, through the following three short-term thrusts: 1) developing novel and low-complexity resource allocation and beamforming techniques for IRS-assisted systems; 2) studying the integration of IRS with other candidate technologies for next-generation communication systems, such as millimeter wave, non-orthogonal multiple access, and physical layer security; and 3) analyzing and quantifying the effects of various transmission impairments, such as imperfect channel state information, discrete phase shifts, and random phase noise on the performance of IRS-assisted transmission and developing novel signal processing techniques to combat such impairments. The proposed research program will provide a systematic framework to address various design issues in IRS-empowered physical layer transmission, and further boost the performance of next-generation cellular systems. Therefore,  the research findings are anticipated to draw attention from both academia and industry, and lead to research collaboration. Meanwhile, the proposed research program will train and equip highly qualified personnel with essential skills in communication theory and signal processing to contribute to Canada's tech and academic sectors.