  In this paper, we investigate the resource allocation algorithm design for
cooperative cognitive relaying multicarrier non-orthogonal multiple access
(MC-NOMA) systems. In particular, the secondary base station serves multiple
secondary users and simultaneously acts as a relay assisting the information
transmission in the primary network. The resource allocation aims to maximize
the weighted system throughput by jointly optimizing the power and subcarrier
allocation for both the primary and the secondary networks while satisfying the
quality-of-service requirements of the primary users. The algorithm design is
formulated as a mixed combinatorial non-convex optimization problem. We apply
monotonic optimization theory to solve the problem leading to an optimal
resource allocation policy. Besides, we develop a low-complexity scheme to find
a suboptimal solution. Our simulation results reveal that the performance of
the proposed suboptimal algorithm closely approaches that of the optimal one.
Besides, the combination of MC-NOMA and cognitive relaying improves the system
throughput considerably compared to conventional multicarrier cognitive
relaying systems.
