  Providing connectivity to aerial users such as cellular connected unmanned
aerial vehicles is a key challenge for future cellular systems. In this paper,
the use of conjugate beamforming for simultaneous content delivery to an AU
coexisting with multiple ground users is investigated. In particular, a content
delivery network of uniformly distributed massive MIMO enabled ground base
stations serving both aerial and ground users through spatial multiplexing is
considered. For this model, the successful content delivery probability is
derived as a function of the system parameters. The effects of various system
parameters such as antenna down-tilt angle, AU altitude, number of scheduled
users, and number of antennas on the achievable performance are then
investigated. Results reveal that whenever the AU altitude is below the BS
height, the antennas down-tilt angles yield an inherent tradeoff between the
performance of the AU and the GUs. However, if the AU altitude exceeds the BS
height, down-tilting the BS antennas with a considerably large angle improves
the performance of both the AU and the GUs.
