Research On Modulation And Demodulation Techniques Based On Filter Banks

As a new transportation technique for cognitive radio and 5G in physical layer, filter banks multi-carrier techniques can solve many critical problems,such as the power leakage. Also,it can make spectrum access more flexible.In this paper,we study in the side-lobe suppression and synchronization techniques.Some algorithms have been promoted to improve the performance of side-lobe suppression and synchronization.Firstly,the thesis gives the overview of cognitive radio and filter banks multi-carrier techniques.Also,the thesis describes the related theory.Then,the thesis makes a thorough research of key techniques of suppressing sidelobe.The thesis studied the method of using pulse shaping filter to suppress the power leakage in a single carrier system.Then,it fo-cused on half-band filter,which can decrease the complexity of implementation.Also,the thesis investigated in methods of decreasing power leakage in an OFDM system.The methods consisted of windowing,dual-windowing,inserting guard bands and inserting cancellation sub-carriers.Based on this,the thesis studied the techniques to prevent power leakage in a GFDM system.These methods consisted of designing protocol filters which have narrow transition zone in frequency domain,inserting guard bands and inserting guard symbol-s.Then,the thesis compared the performance of side-lobe suppression of OFDM with that of GFDM.Then,the synchronization techniques in wireless communication systems is studied.Some solutions are promoted in the thesis.Firstly,the thesis studied the synchronization techniques based on preambles in a single carrier system,including the selection of synchronization sequences,corse timing,the estimation and correction of fractional carrier frequency offset and timing error,fine timing,the estimation of integer multiple of carrier frequency offset and the estimation and correction of residual phase error.Based on this,the thesis studied the synchronization techniques in a GFDM system.Simulation results and analysis of synchronization algorithms are given in the last.At last,the hardware implementation of techniques of side-lobe suppression and synchronization is discussed.The thesis give the validation results which are collected in a platform consisted of Matlab and arbitrary waveform generator of suppressing power leakage.Then.by establishing a platform consisted of AD9361,KC705 and Simulink, validation results of synchronization are given.