A step-shaped hierarchical QAM

Abstract

In this paper, a step-shaped hierarchical quadrature amplitude modulation with two high-priority bits, 4/K-stepped θ-QAM, is proposed for K = 22k and k ≥ 3. We provide a construction method of the signal constellation and present a bit-to-symbol mapping for the proposed 4/K-stepped θQAM. Through computer simulations, we present bit error rate performance of 4/K-stepped θ-QAM in single-input single-output and multi-input multi-output systems by adopting adaptive QR decomposition-M detection and compare with that of the conventional hierarchical constellations.