User Reservation Approach for Peak-to-Average Power Ratio Reduction in MC-CDMA Systems

Multicarrier Code-Division Multiple Access (MC-CDMA) is a foreseen technique for future high data rate and high capacity multiuser wireless communications. However, the often large values of the Peak-to-Average Power Ratio (PAPR) of the transmitted signals pose a problem in multicarrier systems, because they can lead to nonlinear distortion at the High Power Amplifier (HPA) and a subsequent degradation of the system performance. In this paper, we propose a PAPR reduction scheme for MC-CDMA downlink systems based on the addition of peak reduction signals that "borrow" the spreading codes of idle users. The minimization of the PAPR can then be formulated as a Second-Order Cone Programming (SOCP) problem.