Algorithm Research Of Channel Estimation In DVB-T2System

Additive noise, multipath fading and doppler in the Wireless communication channel, are always main factors of effect of performance. Equalization technology directly influences the quality of the receivers. Innovation of DVB-T2technology makes DVB-T2superior, and also brings a lot of problems of equalization.DVB-T2is pilot OFDM system,so its channel estimation algorithm is based on pilots. However, pilots in DVB-T2system have increased up to5types. There are P2pilot and FCL pilot in the beginning and end of frame. Data symbols include edge pilots, continual pilots and scatted pilots which even have8modes. These differences among pilots make channel estimation various. Based on the characteristics of all kinds of pilot, the paper aims to put forward a suitable DVB-T2channel estimation algorithm.The main work is in the follow aspects. Analyze DVB-T2charactersitic, compare DVB-T2with DVB-T, and then put forward channel estimation in frame unit and do special treatment in the beginning and end of frame. P2and FCL pilots in DVB-T2system whose distribution is relatively dense, paper puts forward frequency domain interpolation at first and then filtering in time domain algorithm. PP1-PP7pilots whose distribution is relatively sparse no more than4in time domain, adopt advanced LMS_DFE of DVB-T system which could avoid PI and P2symbol interrupting continuity of data symbols. PP8pilot whose time domain is up to16symbols which couldn’t adopt advanced LMS_DFE algorithm. Given its less pilot number and initial channel characteristic proposed by P2symbol, paper puts forward a coded decision channel estimation algorithm named CD3-Slicer-LMS which adds temporal filtering, constellation decision and LMS algorithm based on CD3-OFDM algorithm.All the improved algorithms are simulated in different radio-frequency channels. In PP1-PP7mode, improved LMS_DFE algorithm with insufficient number of pilot are similar with LMS_DFE with enough number of pilot.In PP8mode, performance from temporal filtering could improve up to0.6dB. After LMS performance of high degree QAM modulation could improve0.2dB.Simulation results show that channel estimation agrees with actual channel model. And DVB-T2equalization algorithm in the paper could meet performance requirements in different static channel.