REDUCING PAPR OF OFDM BASED WIRELESS SYSTEMS USING COMPANDING WITH CONVOLUTIONAL CODES

Abstract

OFDM is a promising broadband technique. However, the implementation disadvantage of OFDM is Peak-to-Average Power Ratio (PAPR) which outweighs all the potential benefits of OFDM. In this paper, a new scheme will be introduced, that combines selective mapping and companding technique to reduce PAPR. However, companding technique is a distortion technique but by using convolutional codes with companding also improves BER performance of the OFDM system. It also removes the disadvantage of SLM technique of extra side information i.e. this technique does not require any side information unlike in conventional SLM. By considering the example of OFDM with BPSK modulation, it is shown in simulation results that the proposed scheme performs well in both reducing PAPR and improving BER performance without the need of any side information. It has been calculated that PAPR of OFDM signal can be reduced by 5dB over the original system with the proposed scheme.