Adaptive Predistortion Techniques for Non-Linearly Amplified FBMC-OQAM Signals

The Filter Bank Multicarrier with Offset Quadrature Amplitude Modulation (FBMC-OQAM) is emerging as one of the alternatives to Orthogonal Frequency Division Multiplexing (OFDM) for next generation broadband wireless access systems. In this paper, we focus on the nonlinear distortion effects in a FBMC-OQAM system when the signal is passed through a nonlinear High Power Amplifier (HPA) which is modeled as Saleh's one exhibiting amplitude and phase distortions. First, we develop an analysis showing that the FBMC-OQAM signals are more sensitive to the phase distortion than OFDM signals. Then, we address the problem of the compensation of these distortions in FBMC-OQAM systems using digital predistortion (DPD) at the transmitter. Therefore, two DPD schemes are considered in this investigation and their performance are compared in OFDM and FBMC-OQAM systems.