Layered-Division-Multiplexing for High Spectrum Efficiency and Service Flexibility in Next Generation ATSC 3.0 Broadcast System

LDM, a non-orthogonal multiplexing technology, is one of the main innovations in ATSC 3.0, a next generation terrestrial TV broadcast system. This article gives a general overview of the LDM technology, its current applications in the ATSC 3.0 system, and its cost in terms of the required additional complexity. The transmission capacity benefit offered by LDM is explained by theoretical analysis and demonstrated by simulation results. An efficient implementation scheme is described with less than 15 percent complexity increase. New service coverage paradigms enabled by LDM are presented. Finally, more future innovative applications of LDM, along with their benefits and challenges, are introduced. These include using LDM for wireless in-band backhaul, combining LDM with scalable video coding, and the application of LDM in other future broadcasting and 4G/5G broadband systems.