Intelligent User Clustering For B5G UAV Base Station Beamforming

With the characteristics of light weight,low cost,high mobility and flexible deployment,UAVs can be used as aerial base stations to expand more possible communication services,thus causing its widely use in various fields.UAV Base Station(UAV-BS)can achieve rapid deployment of communication coverage,ensure the continuity and reliability of mobile communication services,and has unparalleled advantages like mobility over the traditional ground-based fixed base stations.This paper mainly focuses on the beam coverage of clustering area in the millimeter wave(mm Wave)when UAV is used as airborne base station in the setting of B5 G mobile communication.In the first part,this paper investigates the technologies related to millimeter wave communication systems and a detailed analysis of the hybrid beamforming technique and the beamforming technique under Massive-Multi-Input Multi-Output(Massive MIMO),which is also known as 3D-MIMO.Then the channel environment faced by UAVs when used as airborne base stations is explored and analyzed.Finally,this paper studies the clustering analysis algorithm.The features and shortcomings of the traditional DBSCAN clustering algorithm are analyzed in detail.In the second part,this paper explores the region partitioning problem of ground users in the UAV base station coverage area under the sparse millimeter wave channel model.Distinguishing from the traditional region partitioning methods,this paper uses a cluster analysis algorithm to cluster the users and proposes a heuristic iteration-based improved DBSCAN clustering algorithm.By the operation of locally adjusting the density threshold parameter,the limitations of the traditional DBSCAN clustering algorithm are improved to achieve a better clustering effect.In the third part,this paper investigates 3D-MIMO wide-beamforming in the clustered region.Firstly,in order to reduce beamforming complexity and processing time,the clustered region is spatially decoupled from the elevation and azimuth angles of the Uniform Planar Antenna Array(UPA)after coordinate change,making the UPA is divided into two independent uncorrelated horizontal and vertical Uniform Linear Arrays(ULA).Secondly,this paper looks for the maximum elliptical envelope with minimum complete coverage of the transformed region to guarantee the communication service of the edge users in the clustering.Thirdly,the UPA codebook of this system is designed to complete the wide beamforming on the elliptic envelope,so that the actual range of beam coverage is as close to the elliptic envelope as possible,and thus the maximum beam gain can be concentrated on the target clustering area.The research on intelligent user clustering for beamforming of B5 G UAV base stations is meaningful to realize more scalable applications of UAV base stations in the future.