Optimal Deployment Density for Maximum Coverage of Drone Small Cells

In this paper, we intend to study the optimal deployment density of drone small cells (DSCs) to achieve maximum coverage considering the inter-cell interference. Due to the high altitude, the air-to-ground channel of DSCs consist of probabilistic line-of-sight (LoS) and non-line-of-sight (NLoS) links, causing computational difficulties in performance analysis. To accurately analyze coverage performance, we calculate the cumulative inter-cell interference considering both LoS and NLoS links. And we derive an approximate and closed-form expression for it to facilitate the computation of the optimal deployment density in a tractable way. Given the altitude, the optimal deployment density is obtained by determining the optimal coverage radius of a DSC. And numerical results show that, increasing the altitude of DSCs does not necessarily improve coverage performance.