  This work, for the first time, considers confidential data collection in the
context of unmanned aerial vehicle (UAV) wireless networks, where the scheduled
ground sensor node (SN) intends to transmit confidential information to the UAV
without being intercepted by other unscheduled ground SNs. Specifically, a
full-duplex (FD) UAV collects data from each scheduled SN on the ground and
generates artificial noise (AN) to prevent the scheduled SN's confidential
information from being wiretapped by other unscheduled SNs. We first derive the
reliability outage probability (ROP) and secrecy outage probability (SOP) of a
considered fixed-rate transmission, based on which we formulate an optimization
problem that maximizes the minimum average secrecy rate (ASR) subject to some
specific constraints. We then transform the formulated optimization problem
into a convex problem with the aid of first-order restrictive approximation
technique and penalty method. The resultant problem is a generalized nonlinear
convex programming (GNCP) and solving it directly still leads to a high
complexity, which motivates us to further approximate this problem as a
second-order cone program (SOCP) in order to reduce the computational
complexity. Finally, we develop an iteration procedure based on penalty
successive convex approximation (P-SCA) algorithm to pursue the solution to the
formulated optimization problem. Our examination shows that the developed joint
design achieves a significant performance gain compared to a benchmark scheme.
