Ofdm System And Algorithm Simulation

With the increase of demand for the multimedia and with the rapid development of internet,future broadband wireless communication system needs higher data rate.Currently in all the wireless schemes multi-carriers modulation represented by OFDM is one of the most promising ways.As special Multi-Carrier Modulation(MCM) technology,Orthogonal Frequency Division Multiplexing(OFDM) has many orthogonal carrieris each other.Its essense is a sort of multipiexing technology.It has many strengths,such as good performance in fading radio channels, against multipath delay spread,the high rate of spectrum usage efficiency,the strong ability to resist Inter-symbol Interference(ISI),the agile distribution on frequency recource, simple hardware implementation.Moreover, it can transmit data at a high speed in the frequency selective fading channel. However, OFDM system has its faults, such as sensitivity of frequency offset , high Peak-to-Average Power Ratio(PAPR) and phase noice.This paper gives a brief introduction of OFDM (Orthogonal frequency division multiplexing) system's basic principle firstly.According to the define of DFT and IDFT, OFDM technology can be carried out using DSP.It simulates wave shape of OFDM signal according to the European terrestrial digital television (DTV) service.Moreove,the OFDM system's BER-SNR grape is simulated using MATLAB.Channel estimation and reducing high PARA are researched to acquire better capability in this paper.For respective technologies,the thesis summarizes some algorithms from other papers,and researchs on the representative algoritms of them .For example,the LS,ML,MMSE are researched on channel estimation. Channel estimation's importment comes from comb pilot simulation based on LS algorithm,and then the difference is acquired from block pilot simulation based on LS,ML,MMSE algorithms. The choose of channel estimation based on pilot symbols is decided by estimation precision and algorithm complexity.The SLM,PTS are researched on reduing the high PARA. .Simulation on some PAPR reduction schemes such as SLM and PTS was done and results show the advantages and shortcomings of these schemes by comparing with each other.Of course,because SLM is a special kind of PTS.