Spatial Correlation Modeling and Performance Analysis of Urban UAV Networks

Spatial correlation exists in the scheduling of UAVs caused by overlapping conflict between the different UAV groups (UAVG) since the serving UAV can receive interference management requests from other users, especially in urban environments where building blockage will aggravate the scheduling conflict. This letter proposes spatial correlation model in urban UAV networks by Matérn-like model under an interference nulling scheme and derives conflict probability of UAV and the coverage probability, where the non-uniform distribution of LOS/NLOS UAVs and the influence of building blockage effect is theoretically characterized. Specifically, a dynamic UAVG with adjustable radius is organized for each user to perform interference management which considers UAVs distribution forming a 3D conical region depending on the coefficient <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\beta $ </tex-math></inline-formula>, and all UAVs (except the serving UAV) will mute their transmission for interference nulling. In addition, the Matérn-like model ensures that two UAVs in the same UAVG will not simultaneously transmit full power, and thus whether a UAV performs interference nulling is related to other UAVs belonging to the same UAVG. Numerical results show that the simulation of coverage probability fits better with the analytical results which consider spatial correlation.