A Research On The Parameters Estimation Algorithm Of OFDM Signal In Non-cooperative Communication

Orthogonal Frequency Division Multiplexing?OFDM?technology has simple channel equalization;strong resistance ability to frequency selectivity,high spectrum efficiency etc,and it is one of the mainstream technologies of the wireless communication.OFDM technology has huge potential in a variety of communication applications.No matter in military or civil communication applications,due to the advantages of strong resistance to Intersymbol Interference?ISI?,high spectrum efficieny and easy to implement when using large scale intergrated circuit,OFDM has attracted much attention and been widely used.The 4^th Generation mobile communication Long Term Evolution technology?4G LTE?has the advantages of high speed data transmission,good quality data reception and many other ways.OFDM technology is one of the core technologies of 4G LTE and has imcomparable performance to many other technologies.So the non-cooperative communication technology of OFDM signal is of great significance.First of all,the thesis learned the OFDM technology principle and system model,on the basis of OFDM signals in a non-cooperative communication blind identification technology has carried on the thorough analysis.Studied and researched blind estimation technique based on Cyclic Prefix?CP?related,blind estimation based on high-order statistics and blind estimation technique based on cyclic cumulants.Then give a non-cooperative communications OFDM signal blind estimation process.Then,the paper focuses on the non-cooperative communication OFDM radio frequency?RF?signal pretreatment process and blind estimation algorithm for eastimating the time domain parameters.Analylized the process of RF signal's pretreatment including to estimate carrier frequency and channel bandwidth and so on.With the improvement of maximum likelihood?ML?estimation and second-order cyclic cumulants joint estimation algorithm,the thesis first estimated the useful time length and symbol length of OFDM symbol.Then the paper introduces estimation algorithms of other time domain parameters,such as the subcarrier number,sampling rate.Through the analysis and simulation,finally gives the estimate of the time domain parameters of performance analysis.Paper also studied blind synchronization parameter estimation of the non-cooperative communication OFDM signal and realize blind estimation of the parameters for the test bed.Firstly it introduces simulation and performance analysis of the symbol time offset?STO?and carrier frequency offset?CFO?estimation algorithm,improved the ML estimation algorithm for STO estimation.Finally,the paper introduces the blind receiver system based on test bed,including interface,workflow,estimated results show and performance analysis as well as the problems.