تجزیه و تحلیل تکنیک های ترکیبی برای کاهش PAPR در سیستم های ODFM
Abstract: There has been an ongoing research on various PAPR reduction techniques for the multi-carrier systems. There have been several techniques proposed for the PAPR reduction and for efficient power management in the amplifier. Methods such as clipping and filtering, clamping, coding, Partial Transmit Sequence (PTS), Selected Mapping (SLM) and interleaving exists in literature. This project is aimed at carrying out research on how SLM technique works for different set of modulation schemes and for number of subcarriers. Also the SLM scheme is compared with the other methods and performance metrics are analyzed. In addition we show that combining SLM with clipping or with DCT (discrete code transform) coding gives better PAPR results. The coding or the clipping scheme is applied to the IFFT output then the SLM scheme is applied for the signal already dealt by clipping or coding. Clipping scheme tends to miss out data and it removes the peaks which may contain useful data, so we suggest using SLM combined with DCT coding for multicarrier systems. The performance of these PAPR reduction schemes are evaluated by using MATLAB simulation. The analysis is carried out in terms of the complementary cumulative distribution function (CCDF) plot of the PAPR probability. The CCDF of the PAPR denotes the probability that the PAPR of a data block exceeds a given threshold.
Keywords: Orthogonal frequency division multiplexing, Peak-to-average power ratio