On the capacity of multicarrier transmission over nonlinear channels

This paper presents new results on the achievable capacity of multicarrier systems impaired by clipping at the transmitter. A general framework for capacity analysis of multicarrier systems with complex baseband signals is derived, based on the mutual information of the transmitted and received signals. Specific results are given for the soft limiter nonlinearity with different values of the input power backoff (IBO), and for the hard limiter nonlinearity. These capacity results are a true upper bound for multicarrier systems with a large number of subcarriers and can be used for evaluation of receive algorithms for nonlinearly distorted multicarrier signals. It is shown that clipping results only in a small capacity loss even for low IBO.