Massive Connectivity and Massive Content Distribution for Future Wireless Access

无线通信在过去十年中史无前例的增长即将经历另一场技术革命。未来的无线蜂窝网络不仅将实现随时随地的超高速无线接入，还将通过数以百万计的设备提供连接，特别是传感器和执行器，这将有助于实现智能家居、智能汽车和智能城市的愿景。拟议的研究计划将解决未来无线接入的技术挑战，这些挑战是由增强宽带和大规模连接的多种不同需求驱动的。 该提案将调查海量内容分发的基本限制，特别是认识到利用网络边缘的存储和缓存能力以打破无线蜂窝网络中多小区干扰的根本障碍的机会。在基站(BS)和远程终端缓存用户内容的机会导致了网络的以内容为中心的观点，其中诸如文件流行度、用户关联策略、协作和干扰缓解技术等参数之间的交互引起了所提议的研究计划将致力于解决的具有挑战性的系统优化问题。此外，无线组播的机会导致了编码缓存的可能性，这产生了新的内容交付策略，可以显著降低网络回程需求。拟议的研究将仔细建模这些由云计算和缓存能力启用的新传输模式，并将缓存、BS协作和干扰消除机会引入无线干扰信道模型，以得出对蜂窝网络内容交付能力的新理解。 未来的无线网络不仅将显著增强宽带接入，还将为环境监测、传感和控制应用提供跨大量设备的连接。这些新的通信模式对系统设计提出了重大的新挑战，特别是在设备识别、信道估计和延迟敏感应用中的短包传输方面。这项拟议的研究将认识到设备传输的偶发性，并通过将活动设备识别作为稀疏恢复问题来检查大规模连接的理论基础。这项拟议的研究将调查压缩感知和信息理论之间的相互作用，以说明物理层技术(如大规模MIMO、云处理和协作通信)在海量设备通信中的作用，并了解应该如何设计蜂窝网络来满足未来无线接入的多样化用户需求。

The unprecedented growth of wireless communications in the past decade is about to undergo another technological revolution. Future wireless cellular network will not only enable ultra-high-speed wireless access anytime, anywhere, but also provide connectivity through millions of devices, in particular, sensors and actuators that will help realize the visions of smart homes, smart cars, and smart cities. The proposed research program will tackle the technological challenges of future wireless access driven by the multiple diverging requirements for enhanced broadband and massive connectivity. The proposal will investigate fundamental limits of massive content distribution, particularly in recognition of the opportunities to take advantage of storage and caching capabilities at the network edge in order to break the fundamental barrier of multicell interference in wireless cellular networks. The opportunities to cache user content at both the base-stations (BSs) and remote terminals lead to a content-centric view of the network, in which the interactions between parameters such as file popularity, user association strategy, and cooperation and interference mitigation techniques give rise to challenging system optimization problems that the proposed research program will aim to solve. Further, the opportunities for wireless multicast leads to the possibility of coded caching, which gives rise to new content delivery strategies that can significantly reduce the network backhaul requirement. The proposed research will carefully model these new transmission modes that are enabled by cloud computing and caching capabilities, and will bring caching, BS cooperation and interference cancellation opportunity into the wireless interference channel model in order to arrive at a new understanding of the content delivery capacity of cellular networks. Future wireless networks will not only significantly enhance broadband access, but also offer connectivity across massive number of devices for environmental monitoring, sensing, and control applications. These novel modes of communications present significant new challenges in system design, especially for device identification, channel estimation, and for short-packet transmission in delay sensitive applications. The proposed research will recognize the sporadic nature of device transmissions and examine the theoretical foundation of massive connectivity by casting active device identification as a sparse recovery problem. The proposed study will investigate the interplay between compressed sensing and information theory in order to illustrate the roles of physical layer technologies such as massive MIMO, cloud processing, and cooperative communication in massive device communication, and to understand how cellular networks should be engineered to meet the diverse user requirements for future wireless access.