Performance of DVB-T System under Multipath Fading with LS Channel Estimation and Equalization

Digital Video Broadcast-Terrestrial (DVB-T) is a broadly used digital television standard in use around the globe for terrestrial television transmission. It offers many services and enables efficient use of the available radio frequency spectrum than the previous multiplexing modulation techniques to provide high data rates along with robustness against multipath. However, due to the frequency selectivity of the channel, DVB-T systems show poor performance and high probability of errors. In this research, DVB-T system has been implemented in accordance with European Telecommunications Standards Institute (ETSI), EN 300 744 standard. Simulations and analysis based on performance evaluation of DVB-T system in Portable Indoor (PI), Portable Outdoor (PO), Rural Area (RA6), Rayleigh and Typical Urban (TU6) channel models has been conducted. In order to overcome the distortions caused by the multipath channel, Least Square (LS) channel estimation method has been proposed. BER performance of the system has been analysis for 4, 16 and 64 QAM constellations in all five channels. In order to clarify the results image transmission has been done for all three constellations in mentioned channels. As a result in received image distortion has been appeared as a salt and pepper noise, so that we proposed Median filter to overcome with channel noise. However in 4-QAM and 16-QAM the result was acceptable, in 64-QAM constellation result could not be clarify completely, although in RA6 channel with 24dB SNR and with usage of Median filter good improvement can be observed.