A theoretical characterization of nonlinear distortion effects in OFDM systems

This paper presents a theoretical characterization of nonlinear distortion effects in orthogonal frequency-division multiplexing (OFDM) transmission s ystems. In the theoretical framework developed, it is shown that the effect s on the decision variables of the in-band distortion introduced by a bandp ass memoryless nonlinearity can be described by means of a complex gain and an additive Gaussian term with zero mean and suitable variance; analytical expressions for gain and variance are given. The conditions which allow th is description are emphasized and discussed, As a consequence, a completely analytical procedure to evaluate error probability is also obtained and il lustrated using OFDM/discrete multitone modulation (DMT) systems with recta ngular pulse shaping; for the soft-envelope limiter nonlinearity, a closed form is derived. A comparison with simulation results is carried out to ver ify the accuracy of this method.