Direction Information Aided Precoding for Aeronautical Communication Systems

In this paper, we design a new precoding scheme for multiple-input multiple-output (MIMO) aeronautical communication (AC) systems. Exploiting the direction information of the aerial user equipment (UE), the proposed precoding design is capable of maximizing the transmit power towards the direction of the UE approaching the target cell. Specifically, we first transform the original precoding optimization issue to a linear programming problem, and then derive the complex-valued precoding vector from the transformed variables by extending the Newton-Raphson method. Simulation results show that the proposed precoding scheme can improve the link performance of the UEs with known directions, while ensuring that the performance of the UEs with unknown directions can still be close to that observed in the conventional scheme.