Precoding Design for Drone Small Cells Cluster Network with Massive MIMO: A Game Theoretical Approach

The application of drone small cells (DSCs) which are unmanned aerial vehicles (UAVs) carrying communication payload to complete the construction of the high-altitude base stations, is playing an increasingly important role for providing emergent wireless services in different scenarios. In order to coordinate interference and reduce huge backhaul overhead among static ultra-dense DSCs on the low-altitude platform, the paper studies a DSC cluster precoding network with massive multiple-input multiple-output (mMIMO). Considering the disadvantage of the energy-constrained unmanned aerial base station (UABS), we investigate the problem of designing precoding at cluster DSCs to minimize the transmission power of UABSs. A modified cluster scheme based on the Euclidean distance is adopted to cluster the DSCs. We eliminate the intra-cluster interference via performing the modified zero-forcing method and coordinate the inter-cluster interference to achieve our target of reducing transmit power. A non-cooperative game among the DSC clusters is formulated, and the existence and uniqueness of the Nash equilibrium of the proposed game are proved. The non-convex optimization problem is solved via the iterative methods and the numerical results show the effectiveness of our proposed scheme.