Peak-to-Average Power Ratio (PAR) reduction for acoustic OFDM systems

Abstract

A major drawback of orthogonal frequency division multiplexing (OFDM) is its large peak-to-average power ratio (PAR). Techniques for PAR reduction have been extensively studied for radio communication systems. While these techniques are applicable to acoustic systems, we take a different approach that aims to capitalize on the fundamental differences between the acoustic and radio systems, namely the fact that acoustic transmissions are inherently band-limited. We extend the tone reservation technique to the out-of-band carriers, and design efficient methods for constructing OFDM signals with lower PAR. Two approaches are investigated, one based on a gradient algorithm, and another that uses random sequences. Simulation results show that our technique can provide PAR reduction without the loss in data rate.