Parallel Algorithms For PAPR Reduction Of OFDM Systems

With the development of the so-called information society,data exchange has become more and more frequent,which puts forward higher requirements on the quality and speed of data transmission.Orthogonal Frequency Division Multiplexing(OFDM)is widely used in many communication systems due to its advantages such as high s ignal transmission rate and strong resistance to multipath interference.However,the peak-to-average power ratio(PAPR)is a significant drawback for OFDM technology,which may cause the signal to exceed the linear region of the power amplifier.Therefore,it is necessary to take steps to reduce the PAPR of the OFDM.This dissertation presents many kinds of PAPR reduction algorithms.The main work is as follows:(1)By analyzing and summarizing the most common three types of PAPR suppression techniques,it is concluded that the performance of traditional PAPR suppression techniques is not balanced.In order to get a more balanced algorithm,a detailed introduction to the hybrid technology based on the combination of multiple algorithms is presented in th is paper.Then the serial and parallel structures of the hybrid technology is analyzed and compared.In order to significantly reflect the advantages of parallel architecture,a SLM-PTS algorithm is verified by simulation.The simulation results show that by using the parallel structure,the computational complexity of the joint algorithm is effectively reduced,the mutual interference between the algorithms is avoided,and the PAPR suppression ability of the algorithm is improved.Finally,from the perspective of multi-algorithm Union,a joint algorithm HSP based on Hadamard transform and SLM-PTS algorithm is proposed.(2)Aiming at the shortcomings of slow convergence rate and high computational complexity of ACE-POCS algorithm,a joint algorithm ACE-C based on ACE-POCS algorithm and Clipping algorithm is proposed.The new algorithm effectively reduces the computational complexity of the algorithm by adopting a parallel structure.The simulation results show that the proposed algorithm has faster convergence speed and stronger PAPR reduction ability.However,due to the introduction of pre distortion operation in the algorithm,the BER of the proposed algorithm is increased.The new algorithm achieves a compromise between PAPR suppression capability,computational complexity,and bit error rate performance.(3)In order to further optimize the BER performance of the joint algorithm,the distortion-free SLM algorithm is introduced into the parallel structure,and a SAP-1 algorithm based on ACE-POCS algorithm and SLM algorithm is proposed.In order to make full use of the advantages of the two algorithms,the new algorithm further optimized the parallel structure and added the PAPR comparison process.Through the simulation analys is under different conditions,we can see that compared with the traditional SLM algorithm and the ACE-POCS algorithm,the new algorithm has stronger PAPR suppression,higher stability,excellent performance of BER,and does not significantly increase the computational complexity,and achieves the equilibrium of many aspects of performance.By analyzing the complexity of the SAP-1 algorithm,we find that the SLM algorithm module in SAP-1 algorithm can be further optimized.In order to reduce the computational complexity of the SLM algorithm,an improved SLM algorithm based on the blocking idea is proposed and introduced into the SAP-1 algorithm to obtain the SAP-2 algorithm.The simulation results show that SAP-2 algorithm has all the advantages of SAP-1 algorithm,but the computational complexity is greatly reduced,and the overall performance is the best.