Design of non uniform constellations for layered division multiplexing

In this paper, we focus on the design of Non Uniform Constellations (NUC) in the context of Layered Division Multiplexing (LDM) proposed recently for digital television systems. Because the Physical Layer Pipe for which the Non Uniform Constellation is designed can be used with or without Layered Division Multiplexing, it is important to design a constellation optimized for the waterfall Signal to Noise Ratio (SNR) of both cases. We propose an algorithm to design the constellation while minimizing the average waterfall SNR of both configurations, with and without LDM. Performance results show that the NUC design can provide a gain of up to 0.85dB for 256QAM constellations with a Coding Rate of 9/15.