Hybrid beamforming with relay and dual-base stations blockage mitigation in millimetre-wave 5G communication applied in (VIOT)

Abstract

Wireless millimetre-wave communication has been adopted in fifth-generation telecommunication due to its larger bandwidth, low interference, and higher resolutions. Despite these advantages, millimetre-wave communication faces many limitations due to path loss and blockages in the environment. In this paper, a spectral-efficient hybrid beamforming approach was proposed to increase network connectivity and performance, which involved several processes. A relay node was selected as a forwarder to connect a blocked user to a base station using the multi-objective Squirrel search optimization algorithm. Furthermore, the optimal base station was selected based on significant parameters for effective connectivity using the dynamic Shannon entropy-based Fuzzy VIKOR algorithm. Drone base stations were also deployed to improve the network coverage and quality of service. Furthermore, the connectivity of a drone base station was influenced by its positioning and altitude, which was controlled using the trust-region policy optimization algorithm. The selected base station executed hybrid beamforming based on an accurate channel state information prediction once the user equipment was directly or indirectly (i.e. via relay node or drone base station) connected to it. In particular, the bi-directional gated recurrent unit model was used to accurately predict the channel state information. MATLAB (R2017b) was used to simulate the proposed hybrid beamforming model and evaluate its performance metrics in terms of throughput, spectral efficiency, bit error rate, number of server users, and achievable rate. The robustness of our approach is validated under two scenarios with perfect and imperfect CSI. The obtained results were compared with the results of two previous studies, which showed that the proposed model achieved a significant performance improvement.