A research on improving the performance of OFDMA system by using DCT / IFFT structure

The overall performance of Orthogonal Frequency Division Multiple Access (OFDMA) system is greatly affected by the peak-to-average power ratio(PAPR). To address the PAPR problem, a tone reservation(TR) method based on FFT/IFFT structure is discussed, then we propose to replace FFT by the fast discrete cosine transform(DCT) which could reduce the computational complexity. Moreover, the experiments prove that the system bit error rate(BER) will not be affected and higher PAPR reduction can be achieved.