LDM Versus FDM/TDM for Unequal Error Protection in Terrestrial Broadcasting Systems: An Information-Theoretic View

In this paper, power-based layer-division multiplexing (LDM) is studied as a means to provide unequal error protection in digital terrestrial television (DTT) systems by adopting an information-theoretic approach. LDM can potentially offer fundamental performance gains as compared to traditional time-division multiplexing (TDM) or frequency-division multiplexing due to the reuse by all information layers of all the available time-frequency resources. The main use case of LDM for terrestrial broadcasting is the simultaneous provision of fixed and mobile services in the same channel. Since most DTT networks worldwide are dimensioned for fixed rooftop reception, this paper illustrates the performance comparison between LDM and F/TDM in terms of the capacity-coverage tradeoff of the mobile service for a given reduction of the capacity of the fixed service while keeping the coverage of the fixed service constant. A mathematical formulation, and corresponding numerical results, are provided for different fading channels, including single-input single-output, single-input multiple-output, multiple-input single-output, and multiple-input multiple-output antenna systems, and accounting also for the impact of non-ideal channel coding.