Power Ratio Reduction with OFDM Signals for Broadband Wireless Mobile Communication

With the advancement of technologies in communication field, high data rate in addition to both power efficiency and lower bit error rate have always been areas of interest for scientist. The ever increasing demand of high data rate can be fulfilled by the single carrier modulation along with the tradeoff between the power efficiency and bit error rate. It is very difficult to achieve high data rate for this single carrier modulation with a lower bit error rate performance in the presence of frequency selective fading environment. With considering an advance step towards the multi carrier modulation scheme it is possible to get high data rate in this multipath fading channel without degrading the bit error rate performance. To achieve better performance using multi carrier modulation we should make the subcarriers to be orthogonal to each other i.e. known as the Orthogonal Frequency Division Multiplexing (OFDM) technique. But the great disadvantage of the OFDM technique is its high Peak to Average Power Ratio (PAPR). As we are using the linear power amplifier at the transmitter side so it’s operating point will go to the saturation region due to the high PAPR which leads to in-band distortion and out-band radiation. This can be avoided with increasing the dynamic range of power amplifier which leads to high cost and high consumption of power at the base station. In this paper, some of the important PAPR reduction techniques which have been compared based on computational complexity, bandwidth expansion, spectral spillage and performance in-band signal distortion and out-of-band radiation.