Interference Cancelation for Downlink of Multidrone Auxiliary Communication System With SDM

In situations where ground communication networks are unavailable due to disasters or other reasons, drones can leverage their flexibility as airborne base stations to provide emergency coverage for ground users. However, the Line-of-Sight-dominant (LoS-dominant) channel between the drone small cell (DSC) and ground users often results in strong downlink interference to noncooperative users. This interference can hinder the full utilization of spectrum resources. To address this issue, this article proposes an interference cancelation scheme based on cooperative transmission. This article first discusses the power allocation strategy for the DSC. It then proposes an ideal phase condition, which is shown to be difficult to achieve. Finally, by taking into account the power allocation optimization and phase setting strategy for all base station-user pairs, this article formulates a complete information static game problem. The Nash equilibrium is obtained by combining the strategy equations of all DSCs. Simulation results demonstrate that the proposed scheme effectively eliminates interference in the multidrone auxiliary communication system, and achieves a considerable achievable rate.