  In this paper, we study the resource allocation algorithm design for
multiple-input single-output (MISO) multicarrier non-orthogonal multiple access
(MC-NOMA) systems, in which a full-duplex base station serves multiple
half-duplex uplink and downlink users on the same subcarrier simultaneously.
The resource allocation is optimized for maximization of the weighted system
throughput while the information leakage is constrained and artificial noise is
injected to guarantee secure communication in the presence of multiple
potential eavesdroppers. To this end, we formulate a robust non-convex
optimization problem taking into account the imperfect channel state
information (CSI) of the eavesdropping channels and the quality-of-service
(QoS) requirements of the legitimate users. Despite the non-convexity of the
optimization problem, we solve it optimally by applying monotonic optimization
which yields the optimal beamforming, artificial noise design, subcarrier
allocation, and power allocation policy. The optimal resource allocation policy
serves as a performance benchmark since the corresponding monotonic
optimization based algorithm entails a high computational complexity. Hence, we
also develop a low-complexity suboptimal resource allocation algorithm which
converges to a locally optimal solution. Our simulation results reveal that the
performance of the suboptimal algorithm closely approaches that of the optimal
algorithm. Besides, the proposed optimal MISO NOMA system can not only ensure
downlink and uplink communication security simultaneously but also provides a
significant system secrecy rate improvement compared to traditional MISO
orthogonal multiple access (OMA) systems and two other baseline schemes.
