Improved Method Of Channel Estimation Based On Training Sequences About Self-heterodyne OFDM-ROF System

In order to meet the growing demand for network access bandwidth,the mobile communication service is developing at the rate of gigabit.Radio over fiber combining the high flexibility of wireless access mode with high bandwidth and low loss of fiber communication brings a better experience for the user.Because the DSB ROF system is susceptible to chromatic dispersion,this article based on the analysis of the relevant literature to build a frequency quadruple optical millimeter-wave system reduce chromatic dispersion.The channel estimation method of the system is analyzed and studied.The main completed works are as follows:1.simulation a self-heterodyne single-sideband Radio-over-Fiber for frequency-quadrupled millimeter-wave.A laser and a dual-drive Mach-Zehnder modulator is used to achieve frequency differences of quadrupling the electricity local oscillator,phase-coherent sidebands.The two sidebands was separated by two optical filter,one sideband signal was modulated with a baseband data,another was pure sideband.Coupled into the fiber,at the photodetector beating to get 80GHz modulated millimeter-wave signal,effectively reduced the influence of chromatic dispersion.2.As chromatic dispersion,noise will deteriorate the channel estimation performance,a method based on real-zero interval training sequence combined with interpolation algorithm is proposed to optimize the performance of' channel estimation.The numerical simulation show that the method based on real-zero interval training sequence combined with Cubic Spline Interpolation(Smoothing parameters=0.01)can obtain better performance compared with linear interpolation,a method based on full-real training sequence combined with Intra-symbol frequency-domain averaging algorithm is proposed to improve the channel estimation performance.The numerical simulation shows that when the use of ISFA window length is 31 points,the improvement was best?...