Peak restoration in OFDM receiver with clipping A/D converter

OFDM signals suffer from a large Peak to Average Power Ratio, which requires large power back-offs in the transmit and receive chains. This paper studies two digital postprocessing methods of different complexity that mitigate clipping by the analog-to-digital converter in the receiver. Clipped peaks cause spurious signals on empty subcarriers, which can be used to eliminate clipping artifacts and to recover the original signal. Simulations show that a significant reduction of 3 dB in the headroom of the A/D converter (ADC) is possible, when an elaborate MMSE clip correction algorithm is used. A simple algorithm still allows for 1 dB reduction of the headroom. As the ADC is consuming an ever increasing fraction of the total receiver power, the results are believed to be relevant for low-power design of OFDM receivers, for instance to prolong battery life during digital television reception on mobile phones.