Reduction of PAPR in SFBC-OFDM System Using Clipping and Differential Scaling

Orthogonal frequency-division multiplexing (OFDM) is a well-known technique for transmission of high rate data over broadband frequency-selective channels that mitigates intersymbol interference (ISI) caused by the delay spread of wireless channels. Space Frequency Block Coded technique (SFBC) is a spatial diversity technique used to achieve full transmission diversity with higher capacity. The major drawbacks of OFDM are high Bit Error Rate (BER) and high Peak-to-average power ratio (PAPR). Spacefrequency block coded OFDM system (SFBC-OFDM) is used to reduce the BER and transmit the data. In this paper, the performance of BER vs. SNR in normal OFDM is compared to that of SFBC-OFDM systems using simulation. Simulation results show that the BER in SFBC-OFDM is less than that in normal OFDM. Selective Mapping (SLM) is used as the existing system. In this technique, the minimum PAPR signal is selected and transmitted by generating different representations of OFDM symbols using different phase sequences. Here, the thesis gives an idea to reduce the PAPR using Clipping and differential scaling. The simulation results show that clipping and differential scaling effectively reduces the PAPR. Keywords— Bit-Error Rate (BER), Orthogonal Frequency Division Multiplexing (OFDM), Peak-to-average power ratio (PAPR), Space-Frequency Block Coded-OFDM (SFBCOFDM), Selective Mapping (SLM)