面向突发灾难的无人机应急通信中协同优化理论与方法

Emergency communication systems are very important to emergency rescue in disasters. However, the existing methods are lacking in flexibility, which are limited by the factors such as environment and space. In this project, a UAV emergency communication fundamental framework is established based on the advantages of mobility and hovering of UAVs, which can form the cellular networks with surviving ground base stations cooperatively, also can provide wireless service only via UAVs, and can realize the information exchange between disaster areas and outside at the same time. In addition, the novel methods of cooperative optimization of flight and communication are explored. First, in the scenario with active ground base stations, UAVs cooperate with the surviving base stations to provide wireless service effectively. The new method of cooperative optimization on flight trajectory and communication scheduling to avoid interference is explored, and its low-complexity method is proposed. Thus, the wireless coverage can be achieved without blind areas. Then, in the scenario without ground base stations, the mathematical mechanism for the cooperative optimization of downlink precoding, uplink decoding and transmit power of UAV is explored, and the method of establishing the multi-hop links effectively and rapidly is proposed to provide wireless service outside the serving area. Thus, the scope of wireless coverage can be extended. Last, to realize the information exchange between disaster areas and outside in the above scenarios, the multi-hop UAV relay scheme is proposed for emergency communication. In the scheme, the effective method with approximation to calculate the optimal hovering positions of UAVs is explored when the channel environment is complex and varying, and the number of relays is relatively large. Thus, the information bridge between disaster areas and outside can be built. In this research, the key problems such as wireless information collection, distribution and transmission are solved via UAVs. The theoretical basis and technical support are thus provided for the design of UAV emergency communication networks.

应急通信系统对于突发灾难抢险救援至关重要，但现有手段灵活性差，受环境、空间等因素制约。本项目利用无人机移动、悬停等优势，建立既可与幸存基站协作构建蜂窝网络、又可仅靠无人机提供无线服务、同时实现灾区信息转入转出的无人机应急通信统一框架，探索其中协同优化新思路。1存在地面基站场景，无人机与幸存基站有效配合提供无线服务，探索无人机飞行与通信协同优化规避干扰的新思路并提出低复杂度求解方法，实现无盲区全覆盖；2无地面基站场景，探索无人机基站上下行编解码与功率协同优化的数学机理，并提出迅速建立多跳链路为区域外提供无线服务的方法，拓展覆盖范围；3将上述场景信息有效转入转出，提出无人机多中继应急通信部署方案，探索信道环境复杂多变、中继较多时的最优悬停位置有效近似计算方法，建立灾区与外部的信息桥梁。本研究借助无人机解决灾区无线信息采集、扩散与转出等核心问题，为无人机应急通信网络设计提供了理论依据与技术支撑。

应急通信系统对于突发灾难抢险救援至关重要，但现有手段灵活性差，受环境、空间等因素制约。本项目利用无人机移动、悬停等优势，建立既可与幸存基站协作构建蜂窝网络、又可仅靠无人机提供无线服务、同时实现灾区信息转入转出的无人机应急通信统一框架，探索其中协同优化新思路。具体的研究结果主要包括：(1) 存在地面基站场景，无人机与幸存基站有效配合提供无线服务，提出了无人机飞行与通信协同优化规避干扰的新思路并给出低复杂度求解方法，实现无盲区全覆盖；(2) 无地面基站场景，提出了无人机基站上下行编解码与功率协同优化的数学机理，并建立了迅速建立多跳链路为区域外提供无线服务的方法，有效拓展了覆盖范围；(3) 将上述场景信息有效转入转出，提出了无人机多中继应急通信部署方案，建立了信道环境复杂多变、中继较多时的最优悬停位置有效近似计算方法，建立灾区与外部的信息桥梁。(4) 在上述研究的基础上，本项目还进行了无人机通信其它方向的探索工作，具体包括基于非正交多址接入的无人机通信、无人机通信网络的安全传输、智能反射面辅助的无人机通信等。在本项目的资助下，研究成果发表于IEEE Wireless Commun、IEEE Trans. Commun.、IEEE Trans. Wirel. Commun.、IEEE Trans. Veh. Technol.、IEEE Network、IEEE IoT J.、IEEE Veh. Technol. Mag.、PIMRC、WCSP、ICCC等国际顶级期刊和会议，ESI高引论文6篇，并获辽宁省自然科学奖二等奖、中国电子学会三等奖等学术奖励，授权发明专利5项，其中2项实现了专利转化，培养学生连续两年获辽宁省优秀硕士学位论文，提升了项目组的学术影响力。上述研究借助无人机解决灾区无线信息采集、扩散与转出等核心问题，加快了无人机辅助无线通信的实用化发展，为无人机应急通信网络设计提供了理论依据与技术支撑，应用前景广阔。在未来，将继续针对无人机通信方向的关键问题展开深入研究，将智能反射面与无人机通信结合，实现移动网络的多维立体无线覆盖。