Synchronization Performance Analysis And Algorithm Design Of Time-frequency Cooperative Signal

Weighted Fractional Fourier Transform(WFRFT)is a novel time-frequency analysis tool.In recent years,researchers have tried to apply it in the field of communications.It has shown wide prospect for applications in communications.The signal in the WFRFT domain contains both the time-domain and the frequency-domain information,and the WFRFT processing contains both single-carrier and multi-carrier implementation processes.Therefore,based on the WFRFT,a novel hybrid carrier communication system is built,which is compatible with both single-carrier and multi-carrier system,as well as their characteristics.The communication performance of it will also become different.In this paper,we majorly study the synchronization property of the time-frequency signal after the WFRFT operation.Firstly,this paper summarizes the basic theory of Weighted Fractional Fourier Transform,and then introduces the hybrid carrier modulation based on the WFRFT discrete algorithm.Then we give the model of the WFRFT Hybrid-carrier communication system while making an analysis on its physical meaning.We introduce the basic features of the WFRFT signal,including time waveform,power spectrum.Meanwhile,we study the sensitivity to parameter ? of the hybrid carrier signal performance.Secondly,this paper analyzes the effect of the time and frequency offset in the WFRFT system by mathematical derivation and discovers how the multi-carrier and single-carrier components generate the influence.Then,we study the correlation properties of time-frequency cooperative signal constructed by the WFRFT operation of ZadoffChu sequences.Timing spectrum shows that time-frequency signal performs better than original sequences against frequency offset,which is also verified by simulation under the double-selective channel.Finally,a time-weighted synchronization sequence based on the time-frequency cooperative signal is constructed to meet the synchronization requirement of the hybrid carrier communication system.The new synchronization sequences show great crosscorrelation property even when the parameter ? difference is very small.It is possible to perform a 2-D scan detection at receiver on the parameter ? and time delay to achieve synchronization.Meanwhile,to reduce the complexity of the 2-D scan,a low-complexity detection algorithm based on K-Means is proposed.Simulation results demonstrate that the proposed algorithm has negligible performance degradation with reduced complexity relative to conventional techniques.