An Aerial and Ground Base Station Cooperation Strategy for Supporting UAV Downlink Transmission

This paper proposes an aerial and ground base station cooperation (AG_CoMP) strategy for improving the downlink transmission performance of an aerial UAV user (AUE) in a UAV and cellular integrated network. The AG_CoMP strategy allows both a ground base station (GBS) and an aerial base station (ABS) to participate in BS cooperation, and seeks to reduce the negative impact on the overall network performance. The GBS and ABS closest to an AUE are associated to cooperatively provide downlink transmission of the AUE and a blanking area is defined to disallow nearby GBSs to transmit during the transmission of the AUE in order to reduce the severe interferences from adjacent GBSs. A combination of non-coherent joint transmission and dynamic point blanking is used to reduce the large signaling overhead between the cooperative BSs with the proposed strategy. Simulation results show that compared with two benchmark strategies which use only GBS cooperation and only ABS cooperation, respectively, the proposed AG_CoMP strategy can ensure a relatively good downlink transmission performance, and achieve a better downlink transmission performance when an AUE is at an intermediate altitude between an ABS and a GBS.