Symbol Synchronization And Channel Estimation For Multi-Carrier Modulation Based On Wavelet Packet Transform

Wavelet packet division multiplexing is a technique combing wavelet andwavelet packet theory of mathematics with multi-carrier modulation technique ofcommunication. It provides higher frequency efficiency, better performance resistingfading and interference and more flexibility to implement multirate transmission.The purpose of this paper is to discuss the symbol synchronization and channelestimation techniques for WPDM system. First, based on multi-carrier modulationtechniques, it discusses the fundamentals and performances of multi_carriermodulation technique, expounds on OFDM and WPDM in detail;analyses thenecessity of symbol synchronization and dissertates the feed-forwarddecision-directed(DD) maximum likelihood (ML) symbol timing method. Afterintroducing the characteristics, types, statistic and theoretical models of wirelesschannels, it points out the importance of channel estimation for the mobilecommunication in future, and discusses pilot aided channel estimation techniquemostly. For each part, MATLAB and SIMULINK simulation are done to validate itsperformance in WPDM system.The analyses of theory and experimental results indicate that feed-forward DDML and pilot aided channel estimation can reduce intersymbol interference effectively,decrease error rate and increase QoS of communication greatly.