Blind technique to lower the PAPR of the MC-CDMA system without complexity

The main drawback of the Multi - Carrier Code Division Multiple Access (MC - CDMA) systems is the high Peak - to - Average Power Ratio (PAPR). MC - CDMA is the best candidate for the fourth generation of mobile communications. Many works present techniques to reduce the PAPR like the Partial Transmit Sequence (PTS), Selected Mapping (SLM), Clipping and Filtering and so on, but all are either increases the system complexity or reduce the Bit Error Rate (BER) performance. In this paper, we proposed a technique that is easy to implement and enhance the BER performance at the same time. The key idea of this method is based on a phase changing transform. We have used the Inverse Fast Fourier Transform (IFFT) as a phase re - distributor which consequently will reduce the PAPR at the same time it will enhance the Walsh - Hadamard spreading code when it is not fully loaded. Simulation results show good enhancement with respect of PAPR and the BER approximately doesn´t affected without increasing the complexity.