Power Allocation for SC-FDE-Based CR Systems Under Explicit Primary User Protection

In this letter, we consider the power allocation for a single-carrier (SC)-based secondary user (SU) transmitter (Tx), which transmits concurrently with an SC or multicarrier (MC) primary user (PU) over the same frequency band. A rate maximization problem for the SU system is formulated subject to an SU-Tx power constraint and an explicit rate loss constraint for the PU system. Due to the nonconvexity of the resulting problem, we propose a successive convex approximation approach to solve the problem where in each iteration closed-form solutions are derived for the power allocation variables of the SU-Tx. We further prove that the proposed algorithm is guaranteed to converge to a local optimum of the original nonconvex problem. Simulation results are provided to show the efficacy of the proposed approach.