Drone-Based Spatial MIMO Measurements in Three Dimensions

This paper presents spatial channel measurements using a wireless drone equipped with a lightweight OFDM transmitter that also embeds position data into the signal. At the basestation, a 64-element antenna array in combination with 64 parallel RF chains is used to receive, downconvert and digitize the multi-antenna signal. The massive MIMO channel is further characterized using off-line post-processing by extracting channel state information in the frequency domain. A first result shows the orthogonality cluster structure after applying a k-means algorithm, and the achievable “decorrelation” of users in azimuthal angular space by evaluating pairwise orthogonality in 3-dimensional space.