GFDM System PAPR Reduction Based on MCT Method

The most serious problems of OFDM are the high Out-Of-Band (OOB) Radiation and high Peak-to-Average Power Ratio (PAPR). So that it can’t use the fragmented spectrum and will also increase the system operating costs, reduce efficiency as well. Thus the Generalized Frequency Division Multiplexing (GFDM) comes into being as a candidate for the fifth generation (5G) wireless communication. GFDM can reduce the out-of-band radiation effectively but still suffer from pretty high PAPR. To solve this problem, studies have shown Clipping method can be used to reduce PAPR. However the computational complexity will increase along with the increase of the subcarrier number, and lower clipping threshold will cause severer impact on the signal distortion which is because the Clipping causes irreversible loss on large signals. In this paper, we propose a new method called majorizing compressing and expanding technique (MCT) to suppress the high PAPR of GFDM system. This method compresses high power signals, and expands low power signals at the transmitter and makes the inverse transformation at the receiver, so that the signal amplitude fluctuation is smaller and closer to the average, thus reduces the PAPR. Our simulations also reveal that there is a tradeoff between PAPR reduction and bit error rate(BER) performance. And a comparison between Clipping and MCT will be given to show that MCT performs better.