PAPR reduction in OFDM systems using PTS and various modulation schemes

Day by day number of users and services are increasing rapidly. To accommodate all, very high speed communication systems are required. Orthogonal Frequency Division Multiplexing (OFDM) is an suitable technique for achieving high data rate transmission but the main drawback of OFDM is increase in peak power termed as high peak to average power ratio (PAPR). This high PAPR leads to an in-band distortion due to clipping and out of band radiation due to spectral broadening in power limited devices especially in wireless applications. There are number of techniques have been proposed to attack this problem. In this paper, Partial Transmit Sequence (PTS) technique is considered as it is a distortionless one and reduces peak power significantly. The improvement of PAPR with order of digital modulation schemes is investigated and minimum PAPR phase factors are identified. These phase factors information is transmitted as side information along with desired data. Data is encoded using Low Density Parity Check (LDPC) code as the performance of this code is nearest to the shannon's channel capacity and the results are simulated using MATLAB.