基于凸优化的旋翼无人机基站通信优化

BASE STATION ON ROTARY-WING UAV: A CONVEX OPTIMIZATION APPROACH

李豪健

11849166

硕士

信息与通信工程

王锐

2020-05-29

2020-07-18

哈尔滨工业大学

深圳

无人机市场近几年发展势头迅猛。以大疆为首的中国高新科技企业更是抢占了国际上绝大部分的民用无人机产品市场。除了军事用途外，以无人机作为基站或者通信中继正在成为未来通信系统的一个热门研究方向。在被如地震、海啸等自然灾害摧毁基站、中继等基础通信设施的地区，无人机基站能够迅速部署，为灾区提供基础的通信服务，保证灾区与外界的联系。另外，在一些旅游景点，由于节假日人流量增多，地面基站负载剧增，通信服务基本瘫痪。这时无人机基站也可以快速部署，提高系统的容量，为景区的游客提供通信服务。由于无人机的位置具有高度的灵活性，无人机在空中可以随意移动，且不同的无人机位置会使无人机与用户间的信道条件不同，无人机上携带的电量是有限的。因此，合理设置无人机在空中的三维位置，使得无人机基站给用户提供更好的服务，从而节省发射功率和移动所消耗的能量，就显得非常重要。本文基于现有的无人机通信领域的研究，在无人机基站位置优化算法上进行创新。在假设用户是随机出现的场景下，无人机经过较长的一段时间的观察后累积用户的随机性，计算得出使过去时间内能源效率最大化的无人机三维位置。同时，结合速度约束，用户调度约束等条件，对下一段时间内的无人机的三维位置进行优化，使得求解的问题更贴近实际生活的场景，更具有实用性和现实意义，更能显著提升无人机的系统性能。本文首先从介绍系统的数学模型出发。其信道模型的理论依据主要是Goldsmith的无线通信一书以及已发表文献中的空-地信道模型。无人机基站与用户间的信道模型，主要采用以大尺度衰落为主的信道；用户分布的模型及用户随机出现的模型则是基于泊松点过程；而系统的评价指标则是采用以能量经济性为指标，基于系统吞吐率和旋翼无人机的能量消耗，来衡量优化的效果和系统性能的提升。通过仿真实验的结果可以表明，在对用户的统计分布进行连续的观察后，对无人机的位置进行调整，能够显著地提升无人机基站的能源效率性能表现。

The civil market of Unmanned Aerial Vehicle(UAV) has been developing rapidly in recent years. China's high-tech enterprises, led by DJI, have occupied most of the UAV product market in the world. In addition to military applications, UAV as base station or communication relay is becoming a more and more popular research direction for the future communication system. In the region, where infrastructure has been destroyed by natural disasters, such as earthquakes and tsunamis, UAV base stations can be deployed rapidly to provide basic communication services and ensure the contact between the disaster area and the outside world. In some tourist attractions, the load of ground base station might increase dramatically due to the increase of people flow during holidays, jamming the communication service. The UAV base station can be rapidly deployed to improve the capacity of the system and provide communication services for tourists in the scenic spot, due to the high flexibility of UAV. When UAV is in different position, the channel conditions between UAV and users will be different. The battery carried by the UAV is limited. Therefore, it is necessary to optimize the three-dimensional position of the UAV, so that the UAV base station can provide better services to users, save the transmission power and the energy consumed by the movement.Based on the existing research in the field of UAV communications, the contribution of this dissertation lies in the optimization algorithm design for UAVs’ locations. Under the assumption that the users appear randomly, the UAV accumulates the user's randomness after a long period of observation, and calculates the three-dimensional location of the UAV via maximizing energy efficiency in the past period of time. Moreover, combined with speed constraints, user scheduling constraints and other conditions, the three-dimensional location of UAV in the next period of time is optimized. This optimization algorithm makes the solution more practical, and can significantly improve the system performance. This dissertation starts by introducing the mathematical system model. The channel model is mainly based on Goldsmith's book of Wireless Communication and the air-ground channel model in the published literature, the user distribution model is based on the Poisson Point Process; and the energy efficiency is used as the performance metric. It is shown by numerical simulations that the proposed optimization algorithms can significantly improve the performance of UAV base stations via continuously observation of user distribution statistics and adaptation of UAVs’ locations.

无线通信 凸优化 随机梯度下降 无人机通信 轨迹优化

wireless communications convex optimization stochastic gradient descent UAV communications trajectory optimization

中文

联合培养

南方科技大学

李豪健. 基于凸优化的旋翼无人机基站通信优化[D]. 深圳. 哈尔滨工业大学,2020.