Higher order adaptive filter based predistortion for nonlinear distortion compensation of radio over fiber links

The biggest limitation of radio over fiber (ROF) links in a wireless network is its limited dynamic range due to `non-linear distortions´ (NLD). In this paper a higher order adaptive filter based modeling and predistortion scheme is proposed to compensate this NLD. The filter is adapted from the distortions of vector-modulated symbols, so that no in-depth knowledge of physical link parameters is needed. Experimental and simulation results show that a third order filter accurately models the ROF link while a second order filter adequately compensates for the phase nonlinearity. The power handling capability of the laser diode is the upper limit in this approach