Joint Channel Estimation for WiMAX by Preamble and Uneven Pilots

The theoretical research on comb-pilot OFDM system is mostly based on pilots´ even distribution 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 to get more accurate joint channel estimation. In the end, the feasibilities and availabilities of this method are proved by simulations on 6 SUI channel modes, and the excellent performances are also confirmed by WiMAX system testing platform.