Peak-to-average power reduction in OFCDM system to enhance the spectral efficiency

As we know every technology has some advantages and issues. OFCDM, which is very promising technique for 4G standard like LTE (Long Term Evolution) and WIMAX (Worldwide Inter-operability for Microwave Access) also has some issues like frequency-offset and PAPR (peak-to-average power ratio). PAPR issue is very severe if it is not considered. Due to PAPR non-linear distortion occurs which causes orthogonality of OFCDM sub-carriers lost, so ICI (Inter Carrier Interference) and ISI (Inter Symbol Interference) both arises. Which is much severe than interference due to pre-OFCDM symbols. Here is a technique known as sub career processing (SCP) technique, that is used to reduce PAPR by more than 5 dB and remove rigorous requirement for power amplifier and digital to analogue converter. Due to PAPR reduction ICI and ISI both reduces drastically.