ML Detection with Symbol Estimation for Nonlinear Distortion of OFDM Signal

In this paper, a new technique of signal detection has been proposed for detecting the orthogonal frequency-division multiplexing (OFDM) signal in the presence of nonlinear distortion. There are several advantages of OFDM communications system. However, one of the existing problems is remain considered as the nonlinear distortion generated by high-power-amplifier at the transmitter end due to the large dynamic range of an OFDM signal. The proposed method is the maximum likelihood detection with the symbol estimation. When the training data are available, the neural network has been used to learn the characteristic of received signal and to estimate the new positions of the transmitted symbol which are provided to the maximum likelihood detector. Resulting in the system performance, the nonlinear distortions of a traveling wave tube amplifier with OFDM signal are considered in this paper. Simulation results of the bit-error-rate performance are obtained with 16-QAM OFDM systems Keywords— OFDM, TWTA, nonlinear distortion, detection.