Clipping noise mitigation methods in DMT-based ADSL systems

Clipping the peak power samples in the DMT signal introduces clipping noise which degrades the system performance. A previous report proposed the spectrum shaping method in which clipping noise is shifted to the high frequency subcarriers that can tolerate higher noise levels. We propose two new clipping noise reduction schemes, one of which is used in conjunction with the spectrum shaping method, to efficiently reduce the clipping noise in ADSL transceivers. The second scheme reduces the clipping noise through a signal randomization, transparent to the receiver. We also study the reduction in clipping noise by combining the two proposed schemes.