A Detection Algorithm for Clipped OFDM Signals Using the IDFT-Matrix

A major drawback of the orthogonal frequency division multiplex (OFDM) principle is the high dynamic range of the transmit signal. The transmit power amplifier (PA) and other elements in the signal path have to operate at high input power backoff (IBO), which decreases the efficiency of the PA and leads to higher costs. This paper presents a novel receive algorithm for OFDM signals with limited dynamic range. The received signal in the time domain (TD) is examined in order to estimate those samples which have not been distorted by the PA. In the frequency domain (FD), some of the most reliable subcarrier symbols are detected. The combination of the information from TD as well as from FD allows the computation of the remaining subcarrier symbols by using a truncated version of an inverse discrete Fourier transform (IDFT) matrix. The simulation results show that this receive algorithm significantly improves the error rate of OFDM systems impaired by clipping at the transmitter.