Directional Antennas Modeling and Coverage Analysis of UAV-Assisted Networks
Jinlin Peng, Wenfei Tang, Hongtao Zhang
Abstract
Existing researches on UAV networks mostly adopt omni-directional antenna pattern, which results in overlapping between coverage areas and bringing severe co-channel interference due to air-to-ground dominant line-of-sight (LOS) channels. Considering directional antennas that concentrate transmission power to small cells, this letter analyzes system performance of UAV-assisted networks with conic directional antenna model by deriving network coverage probability via stochastic geometry, where UAVs and macro base stations (MBSs) are deployed according to independent Poisson point process. Specifically, realistic and mathematically tractable directional antenna pattern is adopted that radiation gain is modeled by a continuous function of the elevation angle <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\varphi $ </tex-math></inline-formula> and the directivity factor <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\omega $ </tex-math></inline-formula> . In addition, the tradeoff between cell association and interference isolation is exploited by adjusting <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\omega $ </tex-math></inline-formula> and UAV LOS/NLOS probabilities. Theoretical results show that, system coverage probability could be improved by 41% in urban environment when <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\omega =6.2$ </tex-math></inline-formula> and UAV density <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\lambda _{u}=300/k{m^{2}}$ </tex-math></inline-formula> .