Ofdm Systems Papr Suppression Technique

In order to overcome the high PAPR of OFDM (Orthogonal Frequency Division Multiplexing) signal, a construction method of multi-phase orthogonal matrix family is proposed and its nature is analyzed in this paper. In the meanwhile, two kinds of low-PAPR (Peak to Average Power Ratio) and guaranteed data security algorithms of OFDM are designed using multi-phase orthogonal matrix. The theoretical analysis and simulation results show that the matrix number of orthogonal matrix family is N!×NN and that the PAPR can be reduced without introducing error rate. In the meanwhile, the data security is guaranteed through taking any matrix as a key and multiplying the OFDM input signals. In addition, the PAPR value of the system can be reduced greatly by combining the pre-coding method with the PTS (Partial Transmit Sequence) technology.A low-PAPR OFDM fusion algorithm is designed in this paper to reduce the redundant information introduced by pulse shaping technology. Firstly, the fusion algorithm analyses the principle of traditional SLM algorithm. Then a new SLM algorithm is designed based on group optimization selection. By regrouping the split input signal based on traditional SLM algorithm, the optional signal sequence number is increased to get a lower PAPR value. Then, the pulse shaping technology is integrated with the group optimization selection SLM algorithm. When the PAPR values are the same, the fusion algorithm integrating pulse shaping technology with the group optimization selection SLM needs less redundant information than that when the pulse shaping technology is integrated with traditional SLM, and the required redundant information is much lower than that of the original pulse shaping technology. The fusion algorithm combining pulse shaping technology and the group optimization selection SLM can reduce the PAPR value and the redundant information significantly without introducing error rate, which makes up the defect of pulse shaping technology that it requires much redundant information.