Analysis of Digital Video Broadcasting – Terrestrial with Different Encoding and Modulation Schemes

Abstract: DVB-T is the most widely used standard for interactive television. DVB-T uses the MPEG-2 standard for coding the data, as well as Forward Error Coding, Reed Solomon Coding and Convolutional coding to make the signal robust against the high amount of error that comes with transmission. It also uses QPSK to modulate the signal, which makes the information be encoded in the phase instead of the amplitude, which also helps with making the signal robust enough for the channel. But due to increase in number of users and changing needs of users in the field of communications and entertainment, there are new challenges that the currents standards are not able to satisfy. So as the number of users increases the system complexity and interference also increases. The communication channel is not free from the effects of channel impairments such as noise, interference and fading. These channel impairments caused signal distortion and signal to ratio (SNR) degradation. This problem can be overcome by implementing the system with different modulation and error detection and correction schemes. So first design a DVB-T system with convolutional coding and OFDM transmitter. Then analyze this system with different modulation schemes such as 64-QAM and QPSK modulation, and find the best suited modulation scheme with lowest bit error rate. Then again analyze this system with different error detection and correction schemes such as Reed-Solomon (RS) encoding and Cyclic Redundancy Check (CRC) encoding to reduce the bit error rate and improves the performance of system.

Keywords: DVB-T, OFDM, BER, RS.