Antenna gain requirements of airborne nodes in mobile core networks

This paper investigates performance and requirements of airborne nodes used as gateway nodes for linking mobile tactical networks together. The use of airborne nodes gives structural advantages in the form of easier regrouping, compared to the classic concept of using semi-mobile masts. However, the airborne nodes have a more limited ability to carry load. We compare three system concepts where airborne nodes are used with a system concept with high gain antennas mounted on masts. For the four concepts we calculate communication ranges using an advanced wave propagation model which takes the terrain profile into account. We also calculate antenna gain requirement of the airborne nodes for their range to become larger than the range of the ground-based radio link. The results suggest that it is not necessarily beneficial to use airborne nodes, unless they are large enough to carry advanced antennas. In the studied system concepts, it seem hard to replace high-gain antennas in masts with ground nodes and an airborne relay node, unless at least some of the ground or airborne nodes have higher antenna gain.