The Research On Peak-to-average Power Ratio Reduction For OFDM Systems

Orthogonal frequency-division multiplexing (OFDM) is a multi-carrier modulation technique with high data rate and high spectrum utilization efficiency, so it is robust to the multipath fading channel and fit for multimedia data transform. It has been regarded and used as one of the core technologies for the fourth generation communication network. But OFDM has inherent drawbacks of high peak-to-average power ratio (PAPR) and it is sensitive to frequency offset. The paper mainly discusses how to reduce PAPR of OFDM system, and there are some simulation results made by MATLAB.Firstly, the basic principle of OFDM is introduced, the distribution of PAPR is analyzed, three methods of reducing PAPR are summarized and basic theory of each method is analyzed in detail. Then tone reservation method (TR) which is one of the methods of reducing PAPR is investigated in detail, on this basis, a new tone reservation method based on the linearity and cyclic shift properties of the DFT is proposed. In this scheme, the cancellation signals are generated by the information tones , the reserved tones are used to transmit the altitude,phase and position of the peak signals. Simulation results show that the algorithm greatly reduces the PAPR of OFDM systems also reduce side Computational complexity.