Giải pháp sử dụng bộ lọc thích nghi Kalman cho hệ thống ước lượng kênh truyền WiMAX di động

Abstract

Mobile WiMAX (Worldwide Interoperability for  Microwave  Access)  system  has  been  recently applied widely in wireless communication systems [1]. WiMAX uses OFDM (Orthogonal Frequency Division Multiplexing) as a technical platform because of high spectral  efficiency  [2].  In  this  paper,  the  channelestimation algorithms were studied for OFDM system for mobile WiMAX. The comb-pilot structure was usedfor  channel  estimation  algorithms.  We  proposed algorithms  of  channel  estimation  based  on  two adaptive filters: Kalman and Extended Kalman, Thesealgorithms  were  compared  with  popular  LS  (Least Square) estimator. The simulation results showed that Estimators based on Kalman Filters had performance improvement  in  slow  fading  condition  with  low Doppler  shift  and  limited  quality  in  fast  fading condition with high Doppler shift.