Cooperation of clipping with companding to improve the BER performance for multicarrier transmission systems with nonlinear HPA

Practical characteristic curve of the high power amplifier (HPA) below the saturation voltage is a nonlinear instead of a rigorous linear function, which indicates that the dominant small signal components in the conventional simplex clipping method will also suffer a nonlinear distortion and consequently, degrades the bit-error-rate (BER) performance of the receiver. In this paper, a novel cooperation scheme of clipping with companding is proposed to enhance the BER performance of multicarrier transmission system. By employing the companding function to compensate the nonlinear characteristics of HPA, the asymptotic undistorted small signals can be obtained after passing through the HPA. It is shown by simulation experiments that the BER as well as the out-of-band radiation performance can be greatly improved with only a slightly complexity increases.