OFDM-Based Turbo-Coded Hierarchical and Non-Hierarchical Terrestrial Mobile Digital Video Broadcasting

The feasibility of terrestrial Digital Video Broadcast (DVB) to mobile receivers is studied and turbo coded performance enhancements are proposed. Initially, the MPEG-2 codec is subjected to a rigorous bit error sensitivity investigation, in order to assist in designing various error protection schemes for wireless DVB transmission. The turbo codec is shown to provide Signal-to-Noise Ratio (SNR) performance advantages in excess of 5–6 dB over conventional convolutional coding both in terms of bit error rate and video quality. Our experiments suggested that—despite our expectations—multi-class data partitioning did not result in error resilience improvements, since a high proportion of relatively sensitive video bits had to be relegated to the lower integrity subchannel, when invoking a powerful low-rate channel codec in the high-integrity protection class. Nonetheless, DVB transmission to mobile receivers is feasible, when using turbo-coded OFDM transceivers at realistic power-budget requirements under the investigated highly dispersive fading channel conditions. It is interesting to note furthermore that the 5–6 dB SNR improvement due to turbo coding allows us to invoke for example the double-throughput 16-level Quadrature Amplitude Modulation (16-QAM) mode instead of the standard convolutional-coded 4-QAM mode. This facilitates doubling the bit rate and hence improving the video quality. Index Terms—DVB, DVB-T, error sensitivity, hierarchical video transmission, mobile video broadcast, MPEG-2, OFDM, QAM, terrestrial video broadcast, wireless video broadcast