DCT BASED PARTIAL TRANSMIT SEQUENCE TECHNIQUE FOR PAPR REDUCTION IN OFDM TRANSMISSION

OFDM is used as a resource sharing multiple access technique in 4G technology which has several advantages of high data rate, good spectral efficiency, robust against frequency selective fading, etc. Major disadvantage of this system is high peak-to-average power ratio which degrades the performance of power amplifier. In order to overcome this problem, several distortion and distortion-less algorithms have been proposed. Partial Transmit Sequence (PTS) is one of the distortions-less technique which divides the input sequence into subsequences and chooses the phase optimized minimum PAPR signal for transmission. In turn to minimize the PAPR further, signal energy compaction and reduced autocorrelation of input data sequences is required which will be provided by Discrete Cosine Transform. The proposed method combines Discrete Cosine Transform (DCT) with PTS technique. The proposed scheme applies DCT before and after PTS technique. Simulation results shows that DCT before PTS is having better PAPR reduction performance than the DCT after PTS, conventional PTS and conventional OFDM system. The simulation result for the proposed approaches are discussed which reduces PAPR efficiently.