Disturbance Suppression Method for Holographic Beam Based on Rotary RHS in UAV IoT System

Reconfigurable holographic surface (RHS) exhibits low energy consumption and low cost, which attracts extensive attention. Since uncrewed aerial vehicle (UAV) is limited by power and volume, holographic beam is suitable for UAV Internet of things (IoT) systems. However, UAV will encounter complex airflow, causing jitter, which indicates necessary suppression method for holographic beam disturbance. To address the challenge, we explore the problem of robust rotary holographic beam, consisting of angle controlling and hybrid holographic beamforming. The problem is formulated as minimizing the sum mean squared error (SMSE) under the beam disturbance. Resolving such nonconvex issues poses considerable difficulty in achieving optimality. A heuristic scheme is proposed, which decouples the angle controlling and hybrid holographic beamforming. Specifically, angle controlling aims to maximize the sum of the mathematical expectations of the disturbed holographic beamforming matrix to mitigate disturbances. Meanwhile, hybrid holographic beamforming minimizes SMSE under beam disturbances to manage multiuser interference. The suppression gain and computational complexity are analyzed theoretically to validate the effectiveness of the proposed scheme. Furthermore, simulation results show that our scheme performs better than benchmark schemes in sum-rate and bit error rate (BER).