Studies On PAPR Suppression Methods For MC-DCSK Communication System

Multi-carrier differential chaos shift keying(MC-DCSK)communication systems suffer from high peak-to-average ratios(PAPRs).The power amplifiers in these systems may work in non-linear regions,which will distort the transmitted signals and cause serious performance degradation.To alleviate the PAPR problem in the existing MC-DCSK systems,three novel MC-DCSK communication systems are proposed in this thesis.The main work of this thesis is as follows:(1)A novel PAPR suppression method is proposed based on sorting.Pre-processing for sorting input signals is added to the classic multi-carrier multi-level DCSK modulation.The peak-to-average ratio,energy efficiency,spectral efficiency,and system complexity of the system are analyzed,and relavant verification and comparison are given based on Monte Carlo simulations.Simulation results show that the proposed method can effectively reduce the peak-to-average ratio in a multi-carrier multi-level DCSK communication system.(2)Combining carrier index modulation and multi-carrier modulation,a dual-mode multi-carrier differential chao shift keying modulation system is proposed to reduce the peak-to-average ratio as well as improve the spectral and energy efficiencies.The peak-to-average ratio,energy efficiency and spectral efficiency of the new system are analyzed,and corresponding simulation comparisons are also given.Compared with traditional multi-carrier DCSK systems,simulation results show that the proposed system performs better in energy efficiency,spectral efficiency,and better peak-to-average ratio performance.(3)Carrier interference codes are introduced in system in(2)to furtherly reduce the peak-toaverage ratio.The peak-to-average ratio,energy efficiency,spectral efficiency,and system complexity of the new system are analyzed.Besides,the influence of different carrier interfering codes on the peak-to-average ratio in the proposed system is studied by using Monte Carlo simulation,and comparisons based on corresponding simulation results are also given.Compared with system in(2),this new method can suppress the peak-to-average ratio quite well with no performance loss in energy efficiency and spectrum efficiency.