Air-to-Ground Cellular Communications for Airplane Maintenance Data Offloading

Airplane sensors and on-board equipment collect an increasingly large amount of maintenance data during flights that are used for airplane maintenance. We propose to download part of the data during airplane's descent via a cellular base station (BS) located at the airport. We formulate and solve an offline optimization problem to quantify how much data can be offloaded in a non-dedicated band while ensuring that the interference power at the terrestrial BSs in the vicinity of the airport remains below a maximum allowable threshold. Our problem allows for adaptive tuning of transmit power, number of frequency channels to be used, and beamforming according to the position of the plane on the descent path. Our results show that, when the BS at the airport and the plane are equipped with uniform planar arrays, during the last 5 minutes of descent, in the microwave band the plane can offload up to 5GB of maintenance data in a 20 MHz band with a transmit power of 1 W or 40 W. In the mmWave band, the plane can offload up to 24 times more data in a 1 GHz band, with a transmit power of 40 W (using most of the bandwidth) and below 4 times with a transmit power of 1 W (effectively using a maximum of 202 MHz due to bandwidth tuning). Beamforming, power and bandwidth tuning are all crucial in maintaining a good performance in the mmWave band while in the microwave band, dynamic tuning of bandwidth does not improve the performance noticeably.