2016 Volume 5 Issue 7 Pages 236-241
OFDM has great advantages such as high spectral efficiency and robustness against multipath fading. Recently, machine-to-machine (M2M) communications and Internet of Things (IoT) command considerable attention, and the OFDM has been added to a physical layer (PHY) modulation in IEEE802.15.4g standards for smart utility networks (SUN). In this letter, we propose a threshold decision method for maximal-ratio diversity combining in the QAM constellation rearrangement to provide high communication quality with limited hardware resources like in the SUN. It is confirmed that the proposed method can outperform the conventional one without constellation rearrangement at low computational complexity.