The optimization of FHT-based ACO-OFDM Atmospheric Laser Communication System in terms of PAPR reduction

The application of orthogonal frequency division multiplexing (OFDM) in atmospheric laser communication is not as wildly as expected. This is should be owing to several problems rooted in OFDM system and the incompatibility between IM and OFDM. Aiming to analyze the major problems and propose optimized solutions, in the first part of this paper, we introduce the application of fast Hartley transform (FHT), as a suitable alternative to FFT, in asymmetrically clipped (AC) OFDM Atmospheric laser communication system. Then we demonstrate the problem of high PAPR embedded in such system. In the following part of this paper, we firstly review and analyze the performance of some standard methods, namely, Clipping, Companding, Selective Mapping (SLM), Partial Transmit Sequence (PTS), used to reduce the high peak to average power ratio (PAPR) caused by OFDM. And then we make some modifications on those methods so that they could be applied on DHT based AC-OFDM atmospheric laser communication system with more effectiveness. Finally, we propose and compare four different PAPR reduction techniques obtained by serialization of those modified methods. And by using Matlab simulation we demonstrate the feasibility of the proposed methods.