# Using Orthogonal Frequency Division Multiplexing ( Ofdm )

1796 WordsAug 25, 20158 Pages

Abstract multiple carriers are simultaneously modulated using Orthogonal frequency-division multiplexing (OFDM) which is a transmission technique. Since the OFDM-based system has high spectral efficiency and is robust against intersymbol interference and frequency-selective fading channels. The major problem of this system is high peak-to-average power ratio (PAPR) of transmitted signal which causes distortion of signal.
At the Receiver, to reduce PAPR in removing weight with no distortion PAPR reducing scheme which is based on a weighted OFDM signal is proposed. In this scheme, on each discrete OFDM signal through a certain kind of a signal which is band limited a weight is imposed. before a high power amplifier (HPA), an OFDM signal which is formed with the weighted discrete data is then considered, at the receiver side the original signal can be collected completely.
Meanwhile, to transmit the weighted OFDM signal the required time duration is same as the original OFDM signal 's time duration. Computer simulations will evaluate the effectiveness of the scheme which is proposed now. From the numerical results it is observed that , the weighted OFDM signal has bit error rate (BER) performance that is improved when compared with the C&F method and has PAPR smaller than the clipping and filtering (C&F) method. Here, the proposed method is simpler than the clipping and Filtering method. Keywords: Bit error rate, Convolution, Orthogonal Frequency Division Multiplexing