Research On Peak-to-Average Ratio Suppression Technology Based On OFDM System

With the popularization of smart mobile terminals and the rapid development of modern wireless communication technologies,people's demand for data transmission rates is also increasing.Due to the need for a very large data rate and bandwidth to support the communication system,whether it is the first 1G or the current 5G or even the future 6G,the core technology that has been widely used and promoted or the orthogonal frequency division multiplexing technology The technology has many advantages,such as high transmission rate,high frequency universal utilization rate and the ability to resist multipath fading.But OFDM also has shortcomings that cannot be ignored.The most important thing is the excessively high power peak-to-average ratio(PAPR)of the signal.Excessive peak-to-average ratio will not only interfere with the effectiveness of the power amplifier,but also increase the complexity of the system at both the transmitting and receiving ends.Therefore,how to effectively reduce the peak-to-average ratio performance of OFDM systems is currently the main research direction and trend.This paper analyzes and studies the OFDM system peak-to-average ratio reduction technology.First,this article proposes an OFDM system based on Fractional Fourier transform(FRFT)for UWA channels.This system uses FRFT instead of traditional Fourier transform(FFT),and because of the complexity of FRFT The degree is similar to FFT,so this method can significantly improve the system performance without increasing the complexity.The performance of the system is analyzed in depth under various conditions and compared with traditional OFDM.Secondly,based on the above model,the performance of traditional SLM selection mapping technology is analyzed,and an improved SLM method is proposed.This method divides the original OFDM signal into multiple modules and multiplies them by multiple different phase rotation sequences To obtain the lowest PAPR OFDM replacement sequence.Simulation results confirm that this improved block SLM method can obtain excellent PAPR reduction effect with lower complexity.Finally,this paper adds the interleaving technology and linear companding changes to the traditional SLM selection mapping technology,proposes a joint technology based on SLM,and gives the system model of the joint technology.First,compare the performance of several interleaving techniques and choose the best combination of the selected mapping technique.After the linear companding transformation,through the simulation comparison with the mapping method proposed in other literatures,it is verified that the SLM joint technique proposed in this paper has excellent The ability to reduce the PAPR.