Estimation and Cancellation of Nonlinear Companding Noise for Companded Multicarrier Transmission Systems

Nonlinear companding transform (NCT) is an efficient method to reduce the high peak-to-average power ratio (PAPR) of multicarrier transmission systems. However, the introduced companding noise severely restrains the bit-error-rate (BER) performance. In this paper, a general and simple companding noise cancellation (CNC) technique is proposed to mitigate the nonlinear companding noise at the receiver. By exploiting the Bussgang theorem and reconstructing the companding process at the transmitter, the estimated approximate companding noise can be used to refine the received signals. Furthermore, by employing the proposed approach to a typical exponential companding (EC), our results indicate that the proposed scheme can greatly relieve the conventional bottleneck, i.e. the so-called trade-off between the PAPR reduction and BER performance, of NCTs. It shows that for a 512-subcarrier and quadrature phase shift keying modulated orthogonal frequency division multiplexing system, the gap of the signal-to-noise ratio is no more than 0.3 dB at between the ideal performance bound and EC-CNC regardless of the companding degree ( or ) over additive white Gaussian noise channel.