Optimum antenna configurations for millimetre-wave communications from high-altitude platforms

Clustering sizes, power control strategies and antenna beamwidths, and orientations are investigated for quasi-stationary high-altitude platforms (HAPs) or other aerial platforms operating in the millimetre-wave band. It is shown that considering the carrier-to-noise and interference ratios (CNIRs) when optimising antenna beamwidths and directions can lead to significant increases in minimum CNIR levels (e.g. from 8.7 to 16.9 dB) over the coverage area. It is also shown that the optimum antenna configurations and transmit powers are a function of the weather, and should (if possible) be adjusted during periods of cloud cover and rainfall. In more practical situations in which only the transmit powers from the HAP antennas can be adjusted dynamically, it is shown that the loss in performance is <2 dB relative to the optimum scheme with dynamically adjustable antenna beamwidths and orientations over a wide range of rainfall conditions