An Improved SLM Method Based on Hadamard Transform and Four-Dimensional Hyperchaotic Phase Sequences

To reduce Peak-to-Average Power Ratio (PAPR), Selected Mapping (SLM) method can be applied in Orthogonal Frequency Division Multiplexing (OFDM). Transmitting plenty of side information can increase the complexity of the system. To simplify the system and further reduce PAPR, an improved SLM method is proposed, which combines the merits of the four-dimensional chaotic sequences and Hadamard Transform. Firstly, the four-dimensional chaotic sequences produce the random phase sequences, and the random phase sequences is used to transform input data. Then Hadamard Transform is applied . Finally IFFT is used to change every row of the data, and the data with minimum PAPR chosen should be transmitted. Simulation results illustrates that the PAPR performance of the system gotten by the proposed method is better than that of the traditional SLM with the better anti-noise performance.