面向无人机毫米波高效波束搜索的码本优化设计

Optimal Code Book Design for Efficient Beam Search of UAV Millimeter Wave Communication

针对无人机(UAV)动态环境下,波束无法实时匹配这一问题,结合毫米波数字-模拟混合波束形成系统,提出采用一种低复杂度的码本设计方法,以提高波束搜索效率。该方法首先建立了分层波束搜索模型并提出以扇形波束作为训练波束;其次将扇形波束的阵列响应改写为傅里叶级数形式,并利用傅里叶反变换得到扇形波束的理想数字码本;最后通过几何贪婪(Greedy Geometric,GG)算法设计数字基带预编码器和射频预编码器,得到了具有快速搜索能力的优化波束。仿真结果表明,该码本优化方法具有较低的复杂度,有效地提高了波束搜索效率,满足了无人机实时波束匹配需求。

Aiming at the problem that antenna beams cannot be aligned precisely in real time in the environment of unmanned aerial vehicle(UAV),combining the hybrid beamforming system of millimeter-wave,a codebook design method with low complexity is proposed to improve the efficiency of beam search.Firstly,a hierarchical beam search model is established,and the sector beam is adapted as the training beam.Then,the array response of the sector beam is transformed into the form of Fourier series,and the fully-digital codebook is obtained by inverse Fourier transforms.Finally,by using the greedy geometric algorithm,digital baseband precoder and the radio frequency precoder are designed,and the optimized beams with fast searching ability are obtained.Simulations show that the proposed method has lower complexity compared with traditional one,and effectively reduces the search time required by the real-time beam alignment for UAV.