The theoretical research on Comb-pilot OFDM system is mostly based on pilot’s even distributed in whole frequency band. With this even characteristic many interpolation methods are found. While in the WiMAX system many factors should be taken into consideration, which results in that pilots are uneven inserted. In order to apply the theoretical interpolation methods into practical system, we make some modification to a typical interpolation method based on DFT/IDFT. Furthermore, each WiMAX physical frame begins with 2 OFDM preamble symbols which we can use to get coarse channel estimation. We synthesize the uneven pilot estimation and preamble estimation together toget more accuracy joint channel estimation
