Optimal Power Allocation of GFDM Secondary Links With Power Amplifier Nonlinearity and ACI

We investigate the problem of the rate maximization of a generalized frequency division multiplexing (GFDM) based secondary user (SU) link operating over a spectrum hole where adjacent channel interference (ACI) on two active primary users (PUs) in the right and left adjacent channels must be below a threshold. The SU transmitter has nonlinear power amplifier (PA) distortions. We consider a zero forcing (ZF) receiver which removes self-generated interference of GFDM. For a third-order nonlinear PA, we derive the signal-to-interference-plus noise ratio (SINR) and ACI. By using successive convex approximations, we develop a power allocation algorithm to maximize the SU rate subject to the ACI limits on adjacent PUs. Finally, we show that the proposed algorithm improves the SU data rate and that GFDM achieves a higher SU data rate than orthogonal frequency division multiplexing (OFDM).