Research On Peak-to-Average Ratio Reduction Method Based On Advanced Clipping Technology

Cognitive Radio(CR)-based discontinuous Orthogonal Frequency Division Multiplexing(NC-OFDM)modulation technology with its own anti-multipath performance and efficient spectrum utilization has become one of the vital technologies in the fifth generation of mobile communication.However,how to solve the PAPR is still a problem in NC-OFDM systems.It is of great significance to solve the PAPR problem for NC-OFDM technology and to efficiently use spectrum.Based on the traditional clipping technique,this dissertation puts forward an advanced clipping technique to reduce the PAPR in NC-OFDM systems.First of all,the performance of the traditional reduction PAPR techniques is analyzed and compared in NC-OFDM systems.Problems in various schemes are found,that is,partial transmission sequence technology(PTS)and selective mapping technology(SLM)have problems such as high computational complexity and operational difficulty.The mode of traditional clipping technology to reduce signal peak is too single that it is easy to generate system noise and increase bit error rate.Secondly,aiming at the problem of reducing the peak value of the traditional clipping technology,this dissertation proposed a method based on advanced clipping technique to reduce the PAPR.This method improves the singleness problem of reducing the signal peak pattern in the traditional clipping technique.The signal peak value is used at different positions of the scaling factor,and the appropriate scaling factor value and signal peak value are preferentially selected for weighting processing,thereby realizing the PAPR reduction.Finally,the effectiveness of the proposed advanced clipping technique for reducing the PAPR is verified by simulation experiments.And its performance is used to compare with traditional clipping technology,selective mapping technology and partial transmission sequence technology.Result of the experiment shows that,the proposed method has simple operation and improved clipping mode.It not only has good performance advantages in reducing PAPR and bit error rate,but also can effectively avoid signal distortion and reduce system noise.At the same time,the modified signal can be recovered by the filter at the receiving portion to ensure that the user receives more accurate information.