Research On PAPR Reduction Technology In OFDM Systems

Orthogonal frequency division multiplexing is a multi-carrier technologywith strong resistance to multipath fading, strong bandwidth expansibility,flexible allocation of spectrum resources and simple hardware implementation.So, it has been recognized as one of the core technology of the communicationsstandards in the world. However, One of its most important bottleneck is the highpeak to average power ratio. This paper mainly focus on the PAPR of the OFDMsystem to reduce the algorithm to a study.Firstly, this paper first introduces the basic principle of OFDM system, thekey technologies and the advantages and disadvantage of the system, and thendescribed the root causes for the high PAPR of OFDM system, and gives theperformance indicators to measure PAPR. By comparing several commonly usedmethods of PAPR reduction techniques with PAPR suppression performance,complexity of the algorithm and technical advantages and disadvantages. At last,we select the PTS technique of probability class technology as the main contentsof this paper.Calculation of traditional PTS is too complex because of it exhaustive allalternative combinations of phase factors. In this paper, proposing a multi-phasesequence is inverted binary tree method. By symmetrical tree searching, thismethod searches out the optimal phase sequence, change the search process of thephase factor into the process of finding the path of least value of binary tree, andyou can see more clearly the search process of PTS algorithm.After establishing simulation platform with matlab software, we simulatedand analyzed multi-phase sequence is inverted binary tree method. Simulatingresults of Matlab show that the method reduces the system complexity, whilebetter suppress the PAPR. This improved algorithm has better performance on making trade off between the PAPR reduction performance and computationalcomplexity. In practice, we can choose appropriate methods as need.