面向多用户终端直通系统的中继网络协同传输技术研究

Due to the continuous expansion of mobile communication services, future 5G device-to-device (D2D) communication systems would often have multi-user network structures formed by multiple information sources and multiple information destinations in the vicinity. Conventional system design treats each source-destination pair as an independent user link, and, from the whole network’s perspective, does not efficiently utilize the available communication resources. Based on network information theory, this project investigates the principles of applying relay techniques and multi-node coordinated transmissions to improve communication performance in multi-user networks with power-limited devices. The project will carry out joint design of relay transmission protocol, network interference management, and resource optimization, to exploit the potential multiple spatial degrees of freedom (DoF) possessed by multi-user relay networks to realize high-data rate and low-energy consumption communications. It will combine network coding, non-orthogonal multiple access and resource optimization techniques, to efficiently utilize the available spatial diversity to realize high-data rate and low-energy consumption communications. The project will also investigate coordinated transmission strategies to respectively exploit spatial DoF and diversity in delay-sensitive applications, by jointly considering channel state and queue state information. The results of the project will provide new achievable lower bounds to the theoretic performance limits in multi-user relay networks, and will also provide theoretical support and potential key solutions in the design and application of future D2D systems.

随着移动通信业务不断拓展，未来5G终端直通系统必然将出现临近区域内包含大量信源和信宿的多用户网络场景。传统系统设计将每对信源-信宿视为独立用户链路，从整体网络的角度看未能高效利用传输资源。本课题基于网络信息论，研究运用中继技术和多节点协同传输为终端功耗受限的多用户网络提升通信性能的机理。课题将采用对中继转发协议、网络干扰管理与节点资源分配的联合设计，研究利用多用户中继网络潜在具有的多重空间自由度提供高速率、低能耗信息传输的机制。将采用联合网络编码技术、节点非正交接入和资源优化分配策略，研究高效利用网络空间分集提供高速率、低能耗信息传输的机制。并针对对时延敏感的应用场景，综合权衡信道与队列状态，探索充分利用空间自由度和空间分集的中继网络协同传输机制。课题成果将为多用户中继网络的理论极限性能提供新的可达下界，也将为未来终端直通系统的设计和应用提供理论支持和潜在技术方案。

终端直通是指在基站的管理和辅助下，允许临近终端以低能耗、低频谱占用、高复用效率实现高速、快速、可靠的直接数据交互，将是支撑未来智慧交通系统与新一代物联网等多种无线应用的关键技术方案之一。本项目面向多用户终端直通网络，从网络信息论的角度，针对随机衰落、干扰、噪声交互影响带来的挑战，研究运用中继技术与网络级节点协同传输策略提升通信性能，达到高速率、低能耗信息交互的机理。利用多用户多跳中继网络的潜在自由度，依据网络结构和无线衰落特征，建立了协同中继传输与干扰管理机制，提高网络可达自由度与总传输速率；利用多用户协作中继网络的空间分集，提出了将非正交多址接入与网络编码技术相结合，充分平衡频谱利用效率与传输可靠性的协同传输方案，并建立了对复杂衰落与随机干扰时空相关性影响的理论分析框架；面向对时延敏感的应用场景，提出了一系列在动态变化环境中平衡传输机会与传输紧迫性，依据网络信道状态和队列状态，在保证传输需求约束的基础上最大化能量效率的无线传输控制决策方法。项目的研究成果证明了网络级传输设计的优势，为复杂多用户中继网络的极限通信性能建立了新的可达下界，为未来终端直通系统设计提供了基础理论支持与潜在技术方案。