Congratulations for your valuable contribution. We are very interested in your paper as we are focused in communications for other kind of high speed vehicles such as trains.
We are curious about the channel model used for the simulations. In this case you have a channel with high mobility, but there is a quite strong line of sight, hence we think that (different from our case) you are not using a double dispersive channel model. Is this the case? We are very interested in the characterization of the air-to-BS channel.
Thank you very much in advance.
Tomás Domínguez-Bolaño and José Rodríguez-Piñeiro
Yes, we are using single LoS channel for your simulation.
DA2G case, the multi-path is caused by mainly ground surface reflection, building or mountain reflection and other airplane scattering, we assumed.
1. Generally the strongest reflection is by the ground surface reflection.
the lowest position antenna’s tilt is 16 degree and the 3dB beam-width of the antenna is 6 degree, i.e. +/-3 degree. then the lowest angle of the antenna is 13 degree from surface. the antenna transmits weak signal to ground surface. thus we assume the reflected signal from ground surface is weaker than LoS signal.
2. Building or mountain reflection can be controlled by network deployment design and the antenna tilting.
Tall building and mountain location is geographical feature. as same as terrestrial network design, we can manage to reduce the reflection by BS location and antenna direction.
3. the impact by airplane scattering is quite short duration than terrestrial system. the airplane mobility is 800-900km/h. usually they will not do parallel flight like cars on the road. so we consider this is also special case.
these are reasons why we used Los channel model for your simulation. of course, we need the many field trials to finalize the channel model.