MC-CDMA Specific PAPR Reduction Technique Utilising Spreading Code Redistribution

Multicarrier code-division multiple access (MC-CDMA) has been tipped as the technique of choice for future high-data rate fourth generation (4G) wireless systems. It is well known however that multicarrier modulation tends to have high Peak-to-Average Power Ratio (PAPR) which results in nonlinear distortions at the high power amplifier (HPA) and consequently degradation of the Bit Error Rate (BER) performance at the receiver. In this paper we introduce a MC-CDMA specific PAPR reduction technique that uses spreading-code shuffling with the objective to minimise the PAPR at the transmitter. Unlike conventional PAPR reduction techniques proposed so far for orthogonal frequency division multiplexing (OFDM) systems, our technique utilises the characteristic of the CDMA spreading codes to reduce the signal´s PAPR without any loss in system performance. It can be shown that our proposed technique is much less complex and requires far less side information than many of the existing techniques while at the same time achieves significant PAPR reduction.