Performance Analysis Of MIMO-OFDM System

MIMO-OFDM system can enhance the channel capacity and transmission rate highly,and can also deal with the multi-path fading efficiently,so it has become a promising candidate for 4G mobile communication system.This thesis gives a brief introduction about the basic principle and phylogenies of OFDM systems and MIMO systems firstly,based on which the system construction and system model of MIMO-OFDM are given and several key technologies are figured out.Then the thesis mainly researches on the PAPR reduction algorithms of the MIMO-OFDM system.For that,the individual SLM(ISLM)scheme is studied in MIMO-OFDM system.Based on that,to solve the problem that ISLM scheme doesn't benefit additional degrees of freedom provided by the use of multiple antennas scheme,an improved scheme which is SLM scheme with subblocks permutation is proposed.In this algorithm,SLM scheme in each antenna is carried out first of all,then after IFFT the gotten sequences are divided into several subblocks,and at last subblocks are permuted.The additional degrees of freedom provided by the use of multiple antennas scheme can be utilized,so that the PAPR of signals can be reduced furtherly.Simulation results show that the performance of PAPR reduction of presented method is obviously better than that of ISLM scheme.Finally,several representative methods on MIMO-OFDM channel estimation are also presented.