It is well known that there is inherent radiation pattern distortion for the commercial base station antenna array, which usually needs three antenna sectors to cover all space. To eliminate pattern distortion and further enhance beamforming performance, we propose an electromagnetic hybrid beamforming (EHB) algorithm based on 3D superdirective holographic antenna arrays. Specifically, EHB consists of antenna excitation current vectors (analog beamforming) and digital precoding matrices, where the implementation of analog beamforming involves real-time adjustments to the radiation pattern to adapt to the wireless environment. Meanwhile, the digital beamforming is optimized based on the channel characteristics of analog beam-forming to further improve the achievable rate of communication systems. An electromagnetic channel model incorporating array radiation pattern and coupling effect is also developed to evaluate the benefits of our proposed scheme. Simulation results show that the proposed scheme achieves a sum rate gain of over 150 % compared to traditional beamforming algorithms.
Superdirectivity-Based Electromagnetic Hybrid Beamforming for Holographic Communications
Aufsatz (Konferenz)
Elektronische Ressource