The next wave of applications for Unmanned Aerial Vehicles (UAVs) or drones range from delivery of consumer goods or Internet connectivity during natural disasters to defense scenarios such as autonomous combat or search and rescue, all of which require coordination of multiple entities across various altitudes from in-flight to ground-based stations. However, there are two important challenges to realizing such applications. First, positioning many antennas to communicate in three dimensions is non-trivial since the load capacity in terms of power and weight is highly restricted, and the drone body may block reception on the opposite side of the antenna. Second, large-scale antenna arrays are increasingly being used to increase channel quality in a given direction. However, there is limited antenna scale on a single UAV, and the challenge of distributing the antenna array across a drone swarm is extremely complex due to constant mobility, varying relative positions, and the inability to update the channel state of all transmitting nodes. In this project, the goal is to build MuDDI, a Multi-Dimensional Drone Communication Infrastructure, which will enable indoor and outdoor experimentation with UAVs to address research issues related to 3-D connectivity, distributed antennas across a drone swarm, and 3-D swarm formations that optimize the transmission to intended receivers.<br/><br/>To enable these research activities, there are four key development tasks to design such an infrastructure: (i.) building a programmable drone platform to enable hybrid beamforming on each drone to enable directional transmissions across the extremes of all three physical dimensions, which requires antennas on each face of the drone and switching elements to dynamically allocate limited radio frequency (RF) processing chains to these antennas, (ii.) designing a test infrastructure for large-scale distributed beamforming across UAVs for the experimental analysis of the various channel feedback mechanisms that have been set forth but have yet to be evaluated on drones with in-flight vibrations and mobility patterns and various swarm formations, (iii.) constructing and incorporating a large-scale antenna array over the surface of the ceiling and surrounding walls to capture various resulting transmission patterns of a single drone seeking 3-D connectivity, distributed drone swarm creating various formations, and a massive multiple-input/multiple-output (MIMO) ground station, and (iv.) integrating a massive MIMO control station that can enable directional transmissions to, and track the mobility of in-flight systems, enabling research on the various beam widths and multi-user beam patterns that may be simultaneously allocated among large antenna arrays.<br/><br/>This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.