An Improved Method To Reduce PAPR Of OFDM System And Its Performance Analysis

OFDM (Orthogonal Frequency Division Multiplexing), as an important part of modern communication technology, is suitable for high speed wireless communication system, which has strong ability against multipath interference and the band utilization rate, thus, has become the mainstream mobile communication.Although the OFDM system has advantages of digital technology, high transmission rate, and the robustness to frequency selective fading etc; high peak-to-average power ratio (Peak-to-Average Power Ratio, PAPR) still has not been solved. The high PAPR will increase the equipment complexity, affect the transmission performance, raise cost, and limit the use of OFDM technology.While in view of the existing theories and approaches proposed to reduce the PAPR method of the OFDM system, Selective mapping (SLM, selective, mapping) transmitting sequence method, part (PTS, partial transmit sequences) method, carrier protection (TR, Tone Reservation) method, carrier injection(TI, Tone Injection) method and limiting law (clipping) study, this (paper) studies on reduction of OFDM PAPR system, analyze the cause of high PAPR. This paper proposed for a new method for the inhibition of OFDM PAPR system, in use of the simulation with MATLAB software.This paper aims to the study of reducing the PAPR method of the OFDM system. The definition of OFDM PAPR system is suggested firstly. Then the factors of high PAPR are introduced. And then the existing theories and approaches proposed to reduce the PAPR method of the OFDM system are introduced:(SLM) selective mapping, (PTS) partial transmit sequences (TR) Tone Reservation, (TI) Tone Injection and (clipping) study, and the Compressing and Expanding Transform (Commanding Transform). After that, in use of the simulation with MATLAB software, this paper proposes the combined algorithm used to limit the PAPR of OFDM system.Firstly, this paper introduces the basic principle of OFDM system, the key technology, and the main characteristic; secondly, it introduces the PAPR of OFDM system definition, distribution, and basic principles. Then, method of PAPR suppression of the existing OFDM system is studied:(SLM) selective mapping, (PTS)partial transmit sequences (TR)Tone Reservation, (TI)Tone Injection and (clipping) study, and the Compressing and Expanding Transform (Compounding Transform).Afterwards, the existing algorithm is studied, compared with the traditional algorithm, it reduce the amount of calculation of PAPR and decrease the complexity of SLM and PTS algorithm. At the same time PAPR reduction effect is reducer. And then, PTS-Clipping- the combination of clipping algorithm is proposed. Its algorithm principle and MATLAB software is introduced. Furthermore, its complexity is reducer, at the same time PAPR reduction effect is better. In the end, summarizing the main points, the research algorithm is prospected.In the end, summarizing the main points, the research algorithm is prospected.