Research On PAPR Reduction Schemes For OFDM System

Orthogonal Frequency Division Multiplexing (OFDM) scheme has become a popular technique in various high-speed wireless data transmission system, and it has been proposed as a standard for the next-generation mobile radio communication system. OFDM signals have efficient spectral bandwidth, and the performance of the OFDM system against multipath fading is better than that of the single carrier modulation system. One of the major drawbacks of OFDM system is that the OFDM signal of the transmitter can have high peak-to-average power ratio(PAPR), which limits OFDM's wide applications.In this thesis, the PAPR problem and some PAPR reduction methods are researched. We mainly review the selective mapping.(SLM) and the partial transmit sequences.(PTS) scheme to reduce PAPR. The two schemes have good performance of PAPR reduction, but the system complexity restricts the implementation of SLM and PTS. We propose a new SLM scheme by disparting the IFFT conversion and a new PTS scheme by improving the suboptimal iterative algorithm. The two improved schemes reduce the computational complexity, while they almost have the same performace of PAPR reduction as that of the conventionl SLM schemes and PTS schemes.