Research On Location Deployment And Hybrid Beamforming For Multi-antenna UAVs

In recent years,Unmanned Aerial Vehicle(UAV)has been widely used in military,agriculture,meteorology and water conservancy because of its strong maneuverability,high safety,and low cost.In the context of the 5G era,with the soaring amount of access devices in wireless networks,the potential of drones in the field of wireless communications has been fully tapped.It can not only share the network load pressure of the ground station for concerts,movie theaters,stadiums and other hot spots,and increase the access rate,but also can be used as a temporary base station to provide communication services for areas without base stations or damaged base stations.Compared with traditional base stations,the channel conditions established by UAVs are better and are not easily affected by geographical environmental factors.However,UAVs have problems such as location deployment and endurance.In addition,a large amount of research has focused on the application of single-antenna UAVs,and there are few studies on the combination of multi-antenna UAVs and beamforming technology.In this article,in response to the problem of no base station service in a dangerous area or a disaster area,a multi-antenna UAV is deployed to provide communication services for ground user nodes.Since the UAV channel is mainly based on the line-of-sight link,the location of the UAV has a relatively large impact on the overall performance of the system.Considering that the beamforming design is highly related to the position relationship of the UAV and it is difficult to solve it directly,this paper will solve the effective deployment of UAV and the optimization design of hybrid beamforming as the research focus.The main research contents are as follows:First,in the scenario where drones are used as temporary base stations to provide communication services,facing the problem of multi-user communication coverage,a rapid deployment method for drones based on hybrid beamforming with the purpose of minimizing power is proposed.First,an approximate closed expression about the total transmit power is obtained by introducing idealized hybrid beamforming.Then,under the premise of meeting the minimum transmission rate of different users,based on the firefly algorithm,quickly find the best deployment position of the UAV.Comparison and simulation with other deployment methods show that this method can effectively reduce power loss.Second,in combination with the existing hybrid beamforming technology,the hardware and energy loss caused by excessive radio frequency links,a partial connection architecture is adopted at the UAV base station antenna array end.Since it is impossible to directly solve the position and beamforming matrix,a method to optimize the position of the UAV and the hybrid beamforming separately is proposed.First,the virtual channel proposed previously is introduced to solve the position of the UAV,and then the artificial fish swarm algorithm is used to find out the position of the UAV.The best beamforming matrix in the analog domain.In addition,considering the limited resolution,a discrete artificial fish school algorithm is further proposed.Through simulation analysis,it can be seen that the hybrid beamforming method proposed in this paper has better comprehensive performance than other methods,and the deployment position of UAVs is better than other deployment methods.