Coordinated beamforming for high-speed trains in multiple HAP networks

We consider the sum rate achievable throughput between different heuristic coordinated beamforming scenarios, which are the maximum ratio transmission (MRT), zero-forcing beamforming (ZFBF) and the maximum signal-to-leakage-and-noise ratio maximizing beamforming (SLNR-MAX). We assume there is a fixed number of high-altitude-platforms (HAPs) providing simultaneously high-data rate internet access on a fixed number of high-speed trains (HST). We consider the scenarios where the trains are separated apart and crossing each other. Simulation results show that the SLNR-MAX beamforming outperforms the ZFBF and MRT schemes.