Adaptive Scheduling for Millimeter Wave Multi-Beam Satellite Communication Systems

In space information networks, the performance of the satellite-terrestrial links is crucial for downlink data delivery. Due to their relatively wide bandwidth, the use of mmWave (millimeter wave) signals is promising to enhance satellite communications. Adopting on-board antenna arrays can mitigate the attenuation associated with mmWave signals, and can also enable multi-beam transmissions. However, the number of RF (Radio Frequency) chains is usually limited in practical applications, which makes it extremely difficult to properly schedule users. In general, this scheduling problem is NP-hard. In this paper, we propose two scheduling algorithms that can be used to solve this problem with relatively low computational complexity. Intuitively, the correlated users are separated by the proposed schemes, which implies that the spatial diversity gain of multiple beams can be exploited. Simulation results show that the proposed algorithms can achieve nearly optimal performance in terms of the achievable sum rate of the system.