An Adaptive Activated ANN Equalizer Applied in Millimeter-Wave RoF Transmission System

We experimentally demonstrate a 60-GHz radioover-fiber (RoF) system using an adaptive activated artificial neural network nonlinear equalizer (ANN-NLE) to improve the bit error rate (BER) performance. We propose a variable-α activation function ANN-NLE with a faster convergence speed and a stronger equalization ability to solve the nonlinear problems generated from the RoF link. To the best of our knowledge, this letter is the first to apply an adaptive activation function ANN to solve a classification problem and equalize the signals in a 60-GHz RoF system. Using the proposed ANN-NLE, a higher convergence speed and better BER performances can be achieved. Comparisons between our proposed ANN-NLE and nonlinear Volterra equalizer in polynomial structure are reported. Using the proposed ANN-NLE, the system successfully transmits a 5-Gbps BPSK signal through a 10-km fiber and 1.2-m wireless link under a forward error correction limit of 10
^-3
with much higher power sensitivity than the Volterra equalizer.