Non-Uniform and Large Distance Constellation Design for Hierarchical Modulation

In this paper, we newly design a non-uniform QAM signal constellation, which could be appropriately applied for hierarchical modulation. This novel constellation is constructed by a certain number of equilateral triangles and hierarchically divided into two layers; one for MSB and the other for LSB. The advantage of using this constellation compared to uniform rectangular QAM constellation is that the MED for LSB is constantly maintained whereas the MED for MSB is remarkably increased. To this end, we evaluate the performance in terms of SER by means of link level simulation. Consequently, the newly designed constellation does not compromise the modulation performance between MSB and LSB, and the SNR gain of MSB as opposed to uniform rectangular QAM constellation reaches 0.5~0.8dB but without sacrificing the performance of LSB.