Superimposed Training To Reduce The Ofdm Peak To Average More Than Technology

In the broadband wireless mobile communications, an inherent drawback of the Orthogonal Frequency Division Multiplexing technology is that there is a high peak-power and average-power ratio,which exists in MIMO-OFDM technology too. The PAPR problem improves the liearity requirment and complexity of system, but it also affects the signal transmission performance. High PAPR has been one of the main bottlenecks in OFDM and MIMO-OFDM techniques, so it has practical significance to research on how to reduce the system PAPR effectively.This thesis focuses on researching on the algorithm that how to effectively reduce the peak to Average power ratio of the OFDM signal, and using MATLAB software to complete the simulation of the research questions. Around these aspects, this thesis has made the following work:First, the background and current situation of PAPR reduction technology in OFDM are introduced in the thesis.Second, from the basic principle of OFDM start, the thesis analyzes the main advantages and disadvantages of the OFDM technology.Then the innovation of the thesis that's the superimposed training sequence method is introduced, the method is researched relatively less at present but has excellent performance to reduce the PAPR in system. Comprehensive accounting of the complementary performance, the calculation introduction and the band noise and so on, several improved methods integrated with superimposed training sequence method are proposed in the thesis, including companding algorithm with superimposed training sequence, improved SLM technology and parallel SLM algorithm and so on. Based on the theoretical study, the thesis uses the MATLAB software simulation tool to simulate these proposed methods for verifying the performance of algorithms. The selection of superimposed training sequence and its power allocation factor are also considered in the thesis, in order to find the best power allocation factor of training sequence with better performance, and make the algorithms apply accurately and effectively in practical communication system. Finally, the thesis makes the summary carefully on the work has done, and it analyzes the achievements of work and areas for improvement. At the same time, the issues that need to be studied further are proposed in the thesis.