OFDM Systems with Reduced PAPR

Abstract

To reduce peak to average power radio (PAPR) of orthogonal frequency division multiplexing (OFDM) system, flexible and distortion less methods like SLM (Selected mapping) and PTS (Partial transmit sequences) are very useful. The variation of OFDM signal amplitudes is very wide with high PAPR. Huge PAPR necessitates a DAC with sufficient dynamic range to handle the OFDM signals' large peaks. PAPR reduction has been demonstrated to save considerable amounts of energy, with the net power savings being directly proportional to the desired average output power and heavily reliant on the clipping probability level. Here, we concentrate on two recently proposed flexible and distortion less methods for the reduction of the PAR by way of introducing little redundancy. There are two approaches available. A comparison is made between SLM and PTS. The transmitter in SLM selects one favorable transmit signal from a set of suitably varied signals that all represent the same data. In PTS, the transmitter creates a low PAR transmit signal by coordinating the addition of phase rotated signal segments in the proper order. Simulation results are used to compare the schemes in terms of system complexity and redundancy of transmit signals.